long-awaited federal study finally made its debut in
February, recommending significant changes in forensic
science practices and questioning the foundations of
some disciplines. With advice for the scientific and
legal communities, the study from the National Academy of
Sciences may shed heat and light on a debate about crime
laboratories and the admission and weight given to forensic
science testimony. But its sharpest criticisms are unlikely
to lead to consensus among a divided legal community.
““““Strengthening the Forensic Science System in the United
States: A Path Forward””emerges from a committee called for
by Congress in 2006. That directive followed a number of
errors and failures in crime labs, coroners’’offices and
expert testimony. The worst cases were widely reported. In
some, forensic evidence had been stored improperly, lost or
discarded entirely, making it impossible to determine guilt
or innocence using the most recent scientific technology.
Other failures led to what some say were mistaken convictions
and, in at least one case, an execution.
Forensic FailuresAs scientists and lawyers examine the NAS study, they may deter-
mine whether well-publicized failures are representative or atypical.
But many cases, anecdotal or not, are disturbing.
For example, in 2004, the Houston Police Department discovered almost 300 boxes of evidence from the 1970s, boxes that it
had lost. Reports of disorganization and poor systems had plagued
the department’s crime lab since at least 2002. But the discovery
was stunning. The mislabeled boxes contained a vast variety of evidence, much of which would be necessary when a convicted person
seeks to re-test evidence using newer methods. Loss of the evidence
forestalled those attempts.
Poor lab procedures and conditions have been reported at the
FBI and in other states, including Virginia, Ohio, Montana and
In Colorado, the loss, contamination or destruction of biological evidence in crime labs has been reported. Such instances have led
to bills in some states that would require the preservation of evidence for the life of the defendant in major felony crimes; proposals
also include the creation of uniform standards for DNA retention.
Few disagree with the value of preserving such evidence, allow-
ing developments in science to catch up.
In January, for instance, five people were pardoned for the 1985
rape and murder of a Nebraska woman. Improved DNA tests exonerated the defendants, some of whom had pleaded guilty when
threatened with the death penalty. But the Denver Post reported
that the Assistant Attorney General on the case testified this year to
the parole board that the five were innocent, “not beyond a reasonable doubt, but beyond all doubt.”
Preservation is vital. But forensic evidence also can be misused
when it arrives in a courtroom.
In Arizona, Ray Krone was convicted and sentenced to death in
a 1991 rape and murder; a central part of the case against him was
bite-mark testimony, later shown to be faulty. He was exonerated
years later when DNA technology not available at the time of trial
linked another man to the crime.
And in Wisconsin, Robert L. Stinson was convicted of murder
in 1984, but was freed in January after tests found that bite marks
and DNA did not match crime-scene evidence.
Forensic mistakes can be deadly. Cameron Willingham was convicted in the 1992 arson of his Texas home, a fire that killed his
three daughters. Prosecution witnesses in the trial interpreted evidence as indicating a deliberately set fire. The most up-to-date
technology, however, showed the exact opposite. In fact, experts
with the same evidence in other courtrooms testified that other
fires were accidental. Willingham was executed in 2004.
A report on the Willingham case was written by five experts com-
missioned (but not paid) by the Innocence Project, a legal clinic that
seeks to overturn wrongful convictions. But despite what some may
argue is a partisan source, Texas is taking the report seriously.
Like other states, Arizona has taken steps to address changes in sci-
ence that may—or should—lead to changes in forensic science evi-
Following on the work of a task force on DNA and forensic
technology (for its report, see sidebar on p. 16), the Arizona
Attorney General’s Office in 2007 established the Forensic Services