1.
Late one afternoon
in the spring of 1998, a police detective named Shirley McKie stood by the
sea on the southern coast of Scotland and thought about ending her life.
A promising young officer, the thirty-five-year-old McKie had become an outcast
among her colleagues in the tiny hamlet of Strathclyde. A year earlier, she
had been assigned to a murder case in which an old woman was stabbed through
the right eye with a pair of sewing scissors. Within hours of the killing,
a team of forensic specialists had begun working their way through the victim's
house. Along with blood, hair, and fibres, the detectives found some unexpected
evidence: one of the prints lifted from the room where the murder took place
apparently matched the left thumb of Detective McKie.
Crime
scenes are often contaminated by fingerprints belonging to police officers,
and investigators quickly learn to eliminate them from the pool of suspects.
But McKie said that she had never entered the house. Four experts from the
Scottish Criminal Record Office -- the agency that stores and identifies
fingerprints for Scotland's police -- insisted, however, that the print was
hers. Though McKie held to her story, even her father doubted her. "I love
my daughter very much,'' Iain McKie, who served as a police officer in Scotland
for more than thirty years, told me earlier this year. "But when they said
the print was Shirley's I have to admit I assumed the worst. My entire career
I had heard that fingerprints never lie."
Nobody actually
suspected McKie of murder, and in fact the victim's handyman, David Asbury,
was charged with the crime. The sole physical evidence against him consisted
of two fingerprints -- one of his, lifted from an unopened Christmas gift
inside the house, and one of the victim's, found on a biscuit tin in Asbury's
home. The last thing prosecutors needed was for their own witness to raise
questions in court about the quality of the evidence. Yet McKie did just
that -- repeating under oath that she had never entered the house. Asbury
was convicted anyway, but Scottish prosecutors were enraged by McKie's testimony.
As far as they were concerned, McKie had not only lied; she had challenged
one of the evidentiary pillars of the entire legal system. Despite their
victory in the murder trial, they charged McKie with perjury.
Desperate, she went to the public library and searched the Internet for somebody
who might help her. Among the names she came upon was that of Allan Bayle,
a senior forensic official at New Scotland Yard and perhaps the United Kingdom's
foremost fingerprint expert. (It was Bayle's expertise and supporting evidence
that helped convict one of the principal Libyan suspects in the 1988 bombing
of Pan Am Flight 103, over Lockerbie, Scotland.) He agreed to review the
prints, and what he saw astonished him. "It was obvious the fingerprint was
not Shirley's,'' Bayle told me recently. "It wasn't even a close call. She
was identified on the left thumb, but that's not the hand the print was from.
It's the right forefinger. But how can you admit you are wrong about Shirley's
print without opening your-self to doubt about the murder suspect, too?"
Bayle posted a comment on Onin.com, a Web site trafficked regularly by the
world's fingerprint community. "I have looked at the McKie case,'' he wrote.
"The mark is not identical. I have shown this mark to many experts in the
UK and they have come to the same conclusions."
Bayle's assertion
caused a furor. He was threatened with disciplinary action, shunned by his
colleagues, and, after a quarter century with the Metropolitan Police, driven
from his job. But in the end McKie was acquitted, and Bayle's statement helped
challenge a system that had, until then, simply been taken for granted.
2.
For more than a century, the fingerprint has been regarded as an unassailable
symbol of truth, particularly in the courtroom. When a trained expert tells
a judge and jury that prints found at a crime scene match those of the accused,
his testimony often decides the case. The Federal Bureau of Investigation's
basic text on the subject is entitled "The Science of Fingerprints,'' and
a science is what F.B.I. officials believe fingerprinting to be; their Web
site states that "fingerprints offer an infallible means of personal identification.''
The Bureau maintains a database that includes the fingerprints of more than
forty-three million Americans; it can be searched from precinct houses and
properly equipped police cruisers across the country. Fingerprints are regularly
used to resolve disputes, prevent forgery, and certify the remains of the
dead; they have helped send countless people to prison. Until this year,
fingerprint evidence had never successfully been challenged in any American
courtroom.
Then, on January 7th, U.S. District Court Judge
Louis H. Pollak -- a former dean of the law schools at Yale and at the University
of Pennsylvania -- issued a ruling that limited the use of fingerprint evidence
in a drug-related murder case now under way in Philadelphia. He decided that
there were not enough data showing that methods used by fingerprint analysts
would pass the tests of scientific rigor required by the Supreme Court, and
noted the "alarmingly high" error rates on periodic proficiency exams. Although
Judge Pollak later decided to permit F.B.I. fingerprint experts to testify
in this particular case, students of forensic science felt his skepticism
was justified. "We have seen forensic disciplines which focus on bite marks,
hair analysis, and handwriting increasingly questioned in the courts," Robert
Epstein, who had argued for the exclusion of fingerprint testimony in the
case, told me. "But we have accepted fingerprinting uncritically for a hundred
years.''
Epstein, an assistant federal public defender in
Philadelphia, was responsible for the first major court challenge to the
discipline, in 1999, in U.S. v. Byron Mitchell. In that case, Epstein showed
that standards for examiners vary widely, and that errors on proficiency
tests -- which are given irregularly and in a variety of forms -- are far
from rare. The critical evidence consisted of two fingerprint marks lifted
from a car used in a robbery. To prepare for the trial, F.B.I. officials
had sent the prints to agencies in all fifty states; roughly twenty per cent
failed to identify them correctly. "After all this time, we still have no
idea how well fingerprinting really works,'' Epstein said. "The F.B.I. calls
it a science. By what definition is it a science? Where are the data? Where
are the studies? We know that fingerprint examiners are not always right.
But are they usually right or are they sometimes right? That, I am afraid,
we don't know. Are there a few people in prison who shouldn't
be? Are there many? Nobody has ever bothered to try and find out. Look closely
at the great discipline of fingerprinting. It's not only not a science --
it should not even be admitted as evidence in an American court of law."
3.
Fingerprints have been a source of fascination
for thousands of years. They were used as seals on legal contracts in ancient
Babylonia, and have been found embossed on six-thousand-year-old Chinese
earthenware and pressed onto walls in the tomb of Tutankhamun. Hundreds of
years ago, the outline of a hand with etchings representing the ridge patterns
on fingertips was scratched into slate rock beside Kejimkujik Lake, in Nova
Scotia.
For most of human history, using fingerprints to establish
a person's identity was unnecessary. Until the nineteenth century, people
rarely left the villages in which they were born, and it was possible to
live for years without setting eyes on a stranger. With the rise of the Industrial
Revolution, cities throughout Europe and America filled with migrants whose
names and backgrounds could not be easily verified by employers or landlords.
As the sociologist Simon Cole made clear in "Suspect Identities," a recent
history of fingerprinting, felons quickly learned to lie about their names,
and the soaring rate of urban crime forced police to search for a more exacting
way to determine and keep track of identities. The first such system was
devised in 1883 by a Parisian police clerk named Alphonse Bertillon. His
method, called anthropometry, relied on an elaborate set of anatomical measurements
-- such as head size, length of the left middle finger, face height -- and
features like scars and hair and eye color to distinguish one person from
another. Anthropometry proved useful, but fingerprinting, which was then
coming into use in Britain, held more promise. By the eighteen-sixties, Sir
William J. Herschel, a British civil servant in India, had begun to keep
records of fingerprints and use them to resolve common contract disputes
and petty frauds.
Fingerprinting did not become indispensable,
however, until 1869, when Britain stopped exiling criminals to Australia,
and Parliament passed the Habitual Criminals Act. This law required judges
to take past offenses into account when determining the severity of a sentence.
But in order to include prior offenses in an evaluation one would need to
know whether the convict had a previous record, and many criminals simply
used a different alias each time they were arrested. The discovery that no
two people had exactly the same pattern of ridge characteristics on their
fingertips seemed to offer a solution. In 1880, Dr. Henry Faulds published
the first comments, in the scientific journal Nature, on the use of
fingerprints to solve crimes. Soon afterward, Charles Darwin's misanthropic
cousin, Sir Francis Galton, an anthropologist and the founder of eugenics,
designed a system of numbering the ridges on the tips of fingers -- now known
as Galton points -- which is still in use throughout the world. (Ultimately,
though, he saw fingerprints as a way to classify people by race.)
Nobody is sure exactly how Mark Twain learned about fingerprints, but his
novel "Pudd'nhead Wilson," published in 1894, planted them in the American
imagination. The main character in the book, a lawyer, earned the nickname
Pudd'nhead in part because he spent so much time collecting "finger-marks"
-- which was regarded as proof of his foolishness until he astounded his
fellow-citizens by using the marks to solve a murder. If you were to walk
into a courtroom today and listen to the testimony of a typical forensic
expert, you might hear a recitation much like Pudd'nhead Wilson's:
Every human being carries with him from his cradle to his grave certain physical
marks which do not change their character, and by which he can always be
identified -- and that without shade of doubt or question. These marks are
his signature, his physiological autograph, so to speak, and this autograph
cannot be counterfeited, nor can he disguise it or hide it away, nor can
it become illegible by the wear and the mutations of time. ...This signature
is each man's very own. There is no duplicate of it among the swarming populations
of the globe!
Some things have changed since Pudd'nhead Wilson,
of course. A few weeks ago, I visited the headquarters of the Integrated
Automated Fingerprint Identification Systems, the F.B.I.'s billion-dollar
data center, just outside Clarksburg, West Virginia -- a citadel of the American
forensic community. After driving past a series of shacks and double-wides
and Bob Evans restaurants, you come upon a forest with a vast, futuristic
complex looming above the trees. (I.A.F.I.S. moved from more crowded quarters
in the Hoover Building in 1995, thanks to the influence of the state's senior
senator, Robert C. Byrd.)
Clarksburg is home to the world's
largest collection of fingerprints; on an average day, forty thousand are
fed into the system. The I.A.F.I.S. computers, which can process three thousand
searches a second, sort through the database in a variety of ways. For example,
they compare complete sets of fingerprints in the files with new arrivals
-- as when a suspect is held in custody and the police send his "ten-prints"
to I.A.F.I.S. The computer hunts for shared characteristics, and then attempts
to match the prints to a record on file. "We identify about eight thousand
fugitives per month here,'' Billy P. Martin, the acting chief of the Identification
and Investigative Services Section, told me. Martin said that eleven per
cent of job applicants whose fingerprints are entered into the system --
they could be day-care workers, casino staff, federal employees -- turn out
to have criminal records; as many as sixty per cent of the matches are repeat
offenders.
The center looks like a NASA control room, with
dozens of people monitoring the encrypted network of fingerprint machines
sending in data from police stations throughout the country. The main computer
floor is the size of two football fields and contains sixty-two purple-and-gray
"jukeboxes," each filled with two hundred compact disks containing fingerprints.
(There are three thousand sets on each CD.) When someone is arrested, his
prints are initially searched against a state's computer files. If the search
finds nothing, the information is forwarded to the federal database in Clarksburg.
To make a match, the I.A.F.I.S. computer analyzes the many points on the
ridges of every fingerprint it receives, starting with the thumb and working
toward the pinkie; only when the data produce prints that match (or several
prints that seem similar) is the original print forwarded to an analyst for
comparison.
"We used to go to a file cabinet, pull out paper
cards. If it was all loops -- which is the most common type of print -- you
could spend an hour,'' Martin said. "Now a computer algorithm does it in
seconds. The system searches the electronic image against the database and
pulls up the image onto the screen. The accuracy rate on first run is 99.97
per cent.'' Still, this would mean that the I.A.F.I.S. computers make three
hundred mistakes in every million searches. That is where trained examiners
come in. The patterns on fingertips are more like topographical maps or handwriting
than, say, bar codes. They can be so similar that even the most sophisticated
computer program can't tell them apart; it takes a trained human eye to detect
the subtle differences.
I sat with one of the examiners in
a dim, nearly silent room lined with what seemed like an endless series of
cubicles. At each station, someone was staring at a monitor with two huge
fingerprints on it. No two people -- not even identical twins -- have ever
been shown to share fingerprints. The friction ridges that cover the skin
on your hands and feet are formed by the seventeenth week in the womb; at
birth they have become so deep that nothing can alter them, not even surgery.
Look at your fingertips: the patterns resemble finely detailed maps of the
bypasses and exit ramps on modern roads. Experts use the nomenclature of
the highway to describe them: there are spurs, bifurcations, and crossovers.
Some people have fingertips that are dominated by "loops," others by "tented
arches" or small circles that examiners call "lakes," or smaller ones still,
called "dots." Collectively, these details are referred to as minutiae --
an average human fingerprint may contain as many as a hundred and fifty minutia
points. To identify fingerprints, an expert must compare these points individually,
until enough of them correspond that he or she feels confident of a match.
When fingerprints are properly recorded (inked, then rolled, finger by finger,
onto a flat surface, or scanned into a machine that captures and stores each
finger as a digital image), identification works almost flawlessly. The trouble
is that investigators in the field rarely see the pristine prints that can
be quickly analyzed by a computer; most of the prints introduced at criminal
trials are fragments known as "latentprints." Crime scenes are messy, and
the average fingerprint taken from them represents only a fraction of a full
fingertip -- about twenty per cent. They are frequently distorted and hard
to read, having been lifted from a grainy table or a bloodstained floor.
"It is one thing to say that fingerprints are unique and quite another to
suggest that a partial latent print, often covered in blood or taken from
an obscure surface, is unique, identical, or easy to identify,'' Barry Scheck
told me. In the past decade, Scheck, who directs the Innocence Project, has
used DNA evidence to exonerate more than a hundred prisoners, some of them
on death row. "We have always been told that fingerprint evidence is the
gold standard of forensic science. If you have a print, you have your man.
But it is not an objective decision. It is inexact, partial, and open to
all sorts of critics.''
Police use several methods to discover
latent fingerprints. First, they shine a flashlight or a laser along the
clean, solid surfaces on which a print may have been left by the perspiration
and oil on a fingertip. When a print is discovered, detectives use a brush
and powder to mark it, much as they did in the nineteenth century; the powder
clings to the perspiration. (The method works best on smooth surfaces, like
glass.) The print is then photographed and lifted with tape.
The technology for retrieving partial and obscure fingerprints keeps improving.
On a recent episode of the television program "C.S.I.," you might have seen
detectives using a technique called superglue fuming to reveal the outline
of a face on a plastic bag -- an unconventional use of a common practice.
In order to find difficult prints on an irregular surface, such as the human
body, crime-scene investigators blow fumes of superglue over it. As the fumes
adhere to the surface, the ridges of any fingerprint left there turn white
and come clearly into view. Another common method involves ninhydrin, which
works like invisible ink: when you douse paper with it, the chemical brings
out any sweat that may have been left by fingertips. Ninhydrin is particularly
useful with old prints or those covered in blood.
F.B.I. fingerprint
examiners have a variety of computer tools -- a sort of specialized version
of Photoshop -- to help them compare rolled prints with those in their system.
In front of me, an I.A.F.I.S. examiner stared at his computer screen as a
training instructor, Charles W. Jones, Jr., explained the process. "He is
looking for ridges that form dots,'' Jones said. "Bifurcations. Usually they
look for six or seven of those.'' The examiners work around the clock, in
three shifts, and are required to evaluate at least thirty prints an hour.
They know nothing about the people attached to the fingers on their screens;
the prints could be those of a rapist, a serial killer, Osama bin Laden,
a woman applying for a job in the Secret Service, or a bus driver from Queens.
("Yesterday I did fifty-one for a couple hours in a row,'' an examiner told
me proudly.)
At the bottom of the screen there are three buttons
-- "Ident," "Unable," and "Non-Ident" -- and the examiner must click on one
of them. If he identifies a finger, the print goes to a second analyst. If
the two examiners independently reach the same conclusion, the fingerprint
is considered to have been identified. If not, it gets forwarded to an analyst
with more experience. "We have a pretty good fail-safe system,'' Jones said.
"Computers help immensely. But in the end they can't pull the trigger. That's
our job.''
Only a human being can make critical decisions
about identity, and yet the talent, training, and experience of examiners
vary widely. "The current identification system...is only as genuine as the
knowledge, experience, and ability of the specialist carrying out the comparison,''
David R. Ashbaugh, a staff sergeant with the Royal Canadian Mounted Police,
writes, in "Quantitative-Qualitative Friction Ridge Analysis," which is considered
the Bible of the field. And although fingerprint analysis has been in use
for decades, there has never been any consensus about professional standards.
How many distinct characteristics are necessary to prove that a latent fingerprint
comes from a specific person? The answer is different in New York, California,
and London. In certain states, and in many countries, fingerprint examiners
must show that prints share a set number of Galton points before they can
say they have made an identification. Australia and France require at least
twelve matching Galton points; in Italy, the number is sixteen. In America,
standards vary, even within a state. The F.B.I. doesn't require a minimum
number of points; all such regulations were dropped fifty years ago, because,
according to Stephen B. Meagher, the chief of the Bureau's latent-print unit,
the F.B.I. believes that making an identification using Galton points alone
can cause errors.
Meagher says that fingerprint analysis is
an objective science; Robert Epstein, the Philadelphia attorney who has led
the fight against presenting fingerprint evidence in court, says it is not
a science at all. Neither is exactly right. Examining the many contours of
a human finger is not as objective as measuring someone's temperature or
weight, or developing a new vaccine. But it's not guesswork, either. It involves,
inevitably, human judgment, and most people agree that when it is done well
it is highly accurate. The difficulty is in determining whether it has been
done well.
4.
Scientific methodology is based
on generating hypotheses and testing them to see if they make sense; in laboratories
throughout the world, researchers spend at least as much time trying to disprove
a theory as they do trying to prove it. Eventually, those ideas that don't
prove false are accepted. But fingerprinting was developed by the police,
not by scientists, and it has never been subjected to rigorous analysis --
you cannot go to Harvard, Berkeley, or Oxford and talk to the scholar working
on fingerprint research. Yet by the early twentieth century fingerprinting
had become so widely accepted in American courts that further research no
longer seemed necessary, and none of any significance has been completed.
David L. Faigman, who teaches at the Hastings College of the Law and is an
editor of the annually revised forensic text "Modern Scientific Evidence,''
has spent most of his career campaigning to increase the scientific literacy
of judges and juries. Faigman likens the acceptance of fingerprint evidence
to the way leeches were once assumed to be of great medical value. "Leeches
were used for centuries,'' he told me. "It was especially common for the
treatment of pneumonia and it was considered an effective therapy. It wasn't
till late in the nineteenth century that they did the clinical tests to show
that leeches did not help for pneumonia, and they may have actually hurt.
Fingerprinting is like that in at least one crucial way: it is something
we assume works but something we have never properly tested. Until we test
our beliefs, we can't say for sure if we have leeches or we have aspirin"
-- an effective remedy that was used before it was understood. "One of the
things that science teaches us is that you can't know the answers until you
ask the questions.''
The discussion of fingerprinting is only
the most visible element in a much larger debate about how forensic science
fits into the legal system. For years, any sophisticated attorney was certain
to call upon expert witnesses -- doctors, psychiatrists, Bruno Magli shoe
salesmen -- to assert whatever might help his case. And studies have shown
that juries are in fact susceptible to the influence of such experts. Until
recently, though, there were no guidelines for qualification; nearly anybody
could be called an expert, which meant that, unlike other witnesses, the
expert could present his "opinion" almost as if it were fact. Experts have
been asked to testify about he rate at which a tire would skid, and the distance
blood would splatter when a certain calibre bullet smashed into a skull.
They have lectured scores of juries on the likelihood that a medicine could
cause a particular side effect; they have interpreted polygraphs and handwriting,
and have pronounced on whether a bite mark was made by one set of teeth to
the exclusion of all others.
Although forensic evidence has
proved particularly powerful with juries, it is particularly weak as a science.
By the nineteen-eighties, the kind of evidence that was routinely admitted
into court without any statistical grounding or rationale had earned a name:
"junk science." And junk science had become ubiquitous. With the problem
growing out of control, in 1993 the Supreme Court took up a lawsuit called
Daubert v. Merrell Dow Pharmaceuticals. The case involved a child who suffered
from serious birth defects. His lawyers claimed that the defects were caused
by Bendectin, a drug that was for many years routinely prescribed for morning
sickness, which his mother took while she was pregnant. The company argued
that no valid evidence existed to support the claim. The Court's decision
set a new standard for scientific evidence in America: for the first time,
it held that it was not permissible for expert witnesses to testify to what
was "generally accepted" to be true in their field. Judges had to act as
"gatekeepers," the Court said; if an expert lacked reliability he was no
longer allowed in the courtroom. The ruling, and others that expanded upon
it, laid down clear guidelines for the federal bench, requiring judges to
consider a series of questions: Could a technique be tested or proved false?
Was there a known or potential error rate? (DNA identification has provided
the model, because experts have gathered enough statistical evidence to estimate
the odds -- which are astronomical -- that one person's DNA could be traced
to another.) The Court also instructed judges to consider whether a particular
theory had ever been subjected to the academic rigor of peer review or publication.
The Daubert ruling forced federal judges to become more sophisticated about
science, which has not been easy for them. "Daubert changed everything,"
Michael J. Saks, a law professor at Arizona State University, who has written
widely on the subject, told me. "And it is pretty clear when you look at
those criteria that fingerprinting simply doesn't satisfy any of them.''
Since the Daubert ruling, federal courts have judged handwriting evidence
and hair identification to be unscientific. The use of polygraph data has
also been curtailed. Questions have been raised about ballistics -- say,
whether a bullet can be traced back to a particular gun. Somehow, though,
until Judge Pollak came along, challenges to fingerprinting continued to
be regarded as heresy.
Relying largely on testimony presented
by Robert Epstein in U.S. v. Byron Mitchell, the first post-Daubert case
involving fingerprint testimony, Judge Pollak ruled in January that an expert
could say whether he thought fingerprints belonged to the people accused
of the crime, but he could not say that the fingerprints he had examined
were, beyond doubt, those of the defendant.
Pollak is one
of the federal judiciary's most respected judges. Federal prosecutors were
so concerned that any ruling he issued would carry a significance even greater
than its legal weight that they asked the Judge to reconsider his precedent-shattering
decision. Pollak agreed.
Late in February, Pollak held a hearing
on the reliability of fingerprint evidence. For three days, several of the
world's most prominent experts discussed their field in his courtroom. The
F.B.I.'s Stephen B. Meagher testified that no Bureau analyst had ever misidentified
a person in court, and that the Bureau's annual proficiency test was among
the reasons that the Judge should be confident about admitting expert testimony.
Allan Bayle, the British forensic specialist, flew in from London at the
request of the defense. He had a different view. He told Pollak that the
F.B.I.'s proficiency test was so easy it could be passed with no more than
six weeks of training. "If I gave my experts [at Scotland Yard] these tests,
they would fall about laughing," he told Pollak in court. Later, in conversation
with me, he expanded on those comments. "The F.B.I. are conning themselves
and they are conning everybody else,'' he said. "They don't even use real
scene-of-crime marks for the fingerprint tests." He pointed out that the
fingerprints used in the exams were so different from each other that almost
anybody could tell them apart. "Let's say I asked you to look at a zebra,
a giraffe, an elephant, and a lion. Then I asked you to find the zebra. How
hard would that be? What the Bureau should be doing is comparing five zebras
and selecting among them." Bayle and other critics stopped short of calling
fingerprint evidence junk science, but they noted that there are few data
showing how often latent prints are properly identified.
By February 27th, the final day of the hearing, the fissures in an old and
accepted discipline had become visible, and Judge Pollak promised to issue
a final ruling within a couple of weeks.
5.
A few days after Pollak's hearing ended, I flew to Cardiff to attend the
annual meeting of the Fingerprint Society. It was raining in Wales, and the
members of the society were deeply unsettled because their profession was
under assault. Each year, the society gathers for a few days to listen to
lectures and to talk about developments in the field. The society has always
been a club -- the type where you might expect to stumble upon Sherlock Holmes
or G. K. Chesterton. The bar at the Thistle Hotel, where the conference was
held, was filled with police officers from Sussex, Aberdeen, and most places
in between. The conference was well attended by representatives of the United
States Secret Service and the F.B.I. There were also a few stray academics
interested in the latest obscure tech- nology, such as magnetic nanoflake
powders, which are able to capture fingerprints without disturbing whatever
traces of DNA may be present. (With conventional methods, an investigator
has to choose: either swab a mark to harvest the DNA or lift it to find the
print.)
By the time I arrived, the society was preoccupied
by two issues: the Pollak hearings and the lingering ill will from the McKie
case, in Scotland. One of those in attendance was Meagher, the lead F.B.I.
witness in Judge Pollak's courtroom. I introduced myself, and told him that
I understood he couldn't discuss the Philadelphia case while it was under
review, but asked if we could talk about the field in general. "No,'' he
said, without a moment's hesitation. Iain McKie had also come to Cardiff
that weekend, as had Allan Bayle. McKie, a tall, reedy man with a great nimbus
of curly white hair, presented a lecture on the ethics of fingerprinting.
He remained livid about the fact that a fingerprint had destroyed his daughter's
career; although she had been acquitted of perjury, she felt unwelcome on
the police force after having been strip-searched and jailed by her colleagues,
and had resigned soon after her trial. She never returned to work. Today,
she spends much of her time trying to force Scottish authorities to admit
that what they did to her was wrong. "I believe a person made a mistake,
and instead of admitting it they were prepared to send me to jail,'' Shirley
McKie said after she was acquitted of perjury. "It ruined my life, and now
I am trying to pick up the pieces."
The Scottish Criminal
Record Office has never acknowledged the error, nor has the Fingerprint Society
issued any statement about the incident. (David Asbury, the man convicted
of the murder, was released in August of 2000, pending an appeal. As expected,
the judge in the case questioned the validity of the fingerprint evidence
that had led to his conviction.) In Cardiff, McKie told the Fingerprint Society
that the system they represented was "incestuous, secretive, and arrogant.
It has been opened to unprecedented analysis and it's sadly lacking. It pains
me to say that, because I was a police officer for thirty years. You are
indicted on the basis of a fingerprint. You are not innocent till proven
guilty; if the police have a print, you are assumed to be guilty. We need
to start a new culture. The view that the police and fingerprint evidence
are always right, the rest of the world be damned, has to end.''
Afterward, the corridors and conference rooms were buzzing; it was as if
somebody had challenged the fundamentals of grammar at the annual meeting
of the Modern Language Association. But McKie was far from the only speaker
at the conference to raise questions about the field. Christophe Champod,
who works for a British organization called the Forensic Science Service,
has long attempted to apply rigorous statistical methods to fingerprinting.
Champod spoke in an understated and academic manner, but what he had to say
was even more forceful than McKie's presentation. He told the audience that
they had only themselves to blame for the state of the field, that for years
they had resisted any attempts to carry out large trials, which would then
permit examiners to provide some guidance to juries about the value of their
analysis, as is the case with DNA. "What we are trying to do in this field
is reduce, reduce, reduce the population so that there is only a single individual
that can possess a set of fingerprints.... But we can never examine the fingerprints
of the entire universe. So, based on your experience, you make an inference:
the probability that there is another person in the universe that could have
a good match for the mark is very small. In the end, it's like a leap of
faith. It's a very small leap, but it is a leap nonetheless."
Half an hour had been allotted for questions, but there was only silence.
Afterward, one of the organizers explained it to me: "He was using the terms
of religion to describe our science. That's just not fair."
6.
Allan Bayle invited me to visit him in London after the meeting. Bayle is
six feet five with sandy hair and flecks of gray in his blue eyes. He had
recently married and he lives with his wife, child, and mother-in-law just
steps from the M1 motorway entrance in Hendon, on the northern edge of the
city. We sat in his conservatory on a cloudy day while his five-month-old
boy slept in a stroller beside us.
Bayle was frustrated. For
the past five years, he had worked mostly as a lecturer on fingerprints for
the Metropolitan Police. "I taught advanced forensic scene examination, and
I loved it. Once I said I would give evidence in the McKie case, though,
I was no longer allowed to go to meetings. But that is not why I left. They
did nothing about this mistake in identity. When you know something is wrong,
how can you stay silent?" He told me he was particularly upset that Shirley
McKie's career as a police officer had ended for no reason. Bayle's life,
too, has changed. He now works as an independent consultant. Although he
has been portrayed as a critic of fingerprint analysis, he is critical only
of the notion that it should never be questioned. "It's a valuable craft,"
he said. "But is it a science like physics or biology? Well, of course not.
All I have been saying is, let's admit we make errors and do what we can
to limit them. It is such a subjective job. The F.B.I. want to say they are
not subjective. Well, look at what David Ashbaugh -- certainly among the
most noted of all fingerprint analysts -- said when he testified in the Mitchell
case." Ashbaugh had clearly stated that fingerprint identification was "subjective,"
adding that the examiner's talents are his "personal knowledge, ability,
and experience."
Bayle took out a large portfolio containing
dozens of fingerprints, as well as gruesome pictures of crime scenes. "Look
at the mess,'' he said. He showed me a series of photographs: jagged fingerprints
-- black smudges, really -- recovered from the scenes of several murders
he had investigated. "With all that information, you then come to your conclusions.
You have to somehow match that to this clean image'' -- he handed me a picture
of a perfect print, taken at a police booking -- "and say, finally, it's
one man's print. You have got to look at everything, not just points. The
Bureau has not had a missed ident in all their years of working, and I applaud
that. But they are not testing their experts' ability. And that is dangerous.''
7.
The following week, Stephen Meagher agreed
to speak with me at the F.B.I. headquarters, on Pennsylvania Avenue in Washington.
Meagher is perhaps the best known and most forceful advocate for the view
that fingerprint evidence is scientifically valid and that it ought to be
welcome in courts.
"But is it really a science?" I asked as
soon as we settled down to talk in his office. Meagher said that he didn't
think of science as a term that could be easily defined or tailored to fit
all disciplines in the same way. "There is academic science, legal science,
and forensic science,'' he told me. "They are different. You can be an expert
in the field and give testimony without having an academic level of scientific
knowledge.... It is not achievable to take pure science and move it into
a legal arena.'' This seemed surprising, since Meagher had often argued that,
when performed correctly, fingerprint analysis is an "objective'' science.
In 1999, when he was asked in court whether, based on the unique properties
of fingerprints, he had an opinion of the error rate associated with his
work, he said, "As applied to the scientific methodology, it's zero." (Scientists
don't talk this way; it is an axiom among biomedical researchers that nothing
in biology is true a hundred per cent of the time.)
Later,
when I asked David Faigman, the Hastings law professor, whether it made sense
to divide science into legal, academic, and forensic subgroups, he laughed.
"Of course it makes no sense,'' he said. "Mr. Meagher operates
on a sixteenth-century notion -- a Francis Bacon idea -- of what science
is all about. To me, the analogue for law is meteorology. It deals with physics
and chemistry -- the most basic sciences. Yet it has to make predictions
and empirical statements regarding complex reality. That is because so many
factors determine the weather that it's really a probabilistic science. And
I think fingerprinting is the same."
"Most fields of normal
science could pull from the shelf dozens or hundreds, if not thousands, of
studies testing their various hypotheses and contentions, which had been
conducted over the past decades or century, and hand them to the court,''
Michael Saks wrote in "Modern Scientific Evidence." For fingerprinting there
was nothing. In 1999, the F.B.I. conducted its study in preparation for the
Byron Mitchell trial. The study asked examiners to match the two actual latent
prints taken from the car in the Mitchell case with the known set of fingerprints
of the man on trial. Both sets of prints were sent to the crime laboratories
of fifty-three law-enforcement agencies. Of the thirty-five agencies that
examined them and responded, most concluded that the latent prints matched
the known prints of the accused; eight said that no match could be made for
one of the latent prints, and six said that no match could be made for the
other print. The F.B.I., realizing it had a problem, sent annotated enlargements
of all the prints to those examiners who had said the fingerprints couldn't
be matched. In these photographs, the points of similarity on the fingertips
were clearly marked. This time, every lab adopted the F.B.I.'s conclusions.
When I asked Meagher about the study, he told me that the test was supposed
to demonstrate the uniqueness of the prints; it was not meant to be a test
of competency. He claimed opponents have used the data unfairly. At the same
time, he conceded that it would not matter how clean a fingerprint was if
the person examining it hadn't been trained properly. "Our system is a huge
statistical-probability model, but it doesn't make identifications, because
it doesn't have all the information that is needed," he said. "It's a job
for human beings."
8.
On March 13th, Judge
Pollak vacated his earlier order. He issued a new opinion, in which he stated
that the defense had succeeded in raising "real questions about the adequacy
of the proficiency tests taken annually by certified F.B.I. fingerprint examiners."
Yet he was persuaded by the F.B.I.'s record of accuracy, and wrote that "whatever
may be the case for other law-enforcement agencies" the Bureau's standards
seemed good enough to permit F.B.I. experts to testify in his courtroom.
"In short,'' he concluded, "I have changed my mind.'' It was, naturally,
a blow to the opposition -- though Pollak was careful to rule only on the
case before him and only with regard to the F.B.I.
I met with
the Judge shortly after he issued his decision. Having arrived early for
our meeting, I watched as he led the jury-selection process in the case in
which Meagher will now be permitted to testify. Like most courtrooms, it
was decorated with an American flag, but it was filled with art as well:
prints by Matisse, Cézanne, and Eakins and drawings by Victor Hugo lined
the walls.
During the lunch break, we sat in his ramshackle
office. The stuffing was falling out of both of our chairs. Pollak, a lively
man in his late seventies, declined to talk specifically about the case,
but was happy to consider the broader issues it raised. "The most important
question here, of course, is, Am I the right person to be a gatekeeper?''
he said. "I, who know little of science.... As society comes to rely more
fully on technology, the question will become acute.'' Pollak said that he
found it worrisome that the Supreme Court ruling in the Daubert case meant
that he could rule one way on an issue like fingerprints and another federal
judge in a different jurisdiction could do the opposite, and neither ruling
would be reversed (the Court will hear appeals only on procedure, not on
the law). He was frank about how poorly prepared most judges are for making
decisions based on scientific issues.
"I want to tell you
that shortly after I got into this line of work there was no more unqualified
district judge" -- for making such decisions -- "in the United States,''
Judge Pollak said of himself. He told me that in the early nineteen-eighties
he had met a former chief executive of Dupont at a reception. "He asked me
how it can be that people like me are entrusted to make such major scientific
decisions. He wasn't questioning my good faith. But by virtue of my job I
have been asked to make decisions that are out of the range of any competence
that I have." Pollak conceded that the DuPont chairman had a point. I asked
if he felt scientifically competent to rule on the current case in Philadelphia.
He laughed but didn't answer. "I knew when I decided the thing there was
going to be some surprise,'' he said, referring to his initial opinion. "Honestly,
I don't think I had anticipated the degree to which people would be startled....
Other lawyers in fingerprint situations are now almost duty bound to raise
these questions and challenges again. How could they in good faith act in
any other way? This decision is certainly not the end. I think we can be
certain of that.''
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