Barnes was arrested in 1988. At his trial, forensic experts testified that soil, hair, and an imprint from denim on his muddy truck matched samples from Simon. It proved a convincing combination to the jury, along with vague statements from eyewitnesses and a jailhouse snitch. In June 1989, Barnes was convicted and sentenced to 25 years to life in prison.
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Other forensic tests lag behind DNA in several ways. These tests include fingerprinting, as well as the hair, soil, and denim imprint analysis used in Barnes’s trial, and the bite-mark analysis from Krone’s trial. They cannot point to an individual, and little to no research has been conducted toward standardizing them or defining their error rates. Problems arise when attorneys, judges, or juries attach the same aura of reliability to all forensic sciences regardless of their scientific merit, says attorney Josh D. Lee, cochair of the Forensic Science section of ACS’s Division of Chemistry & the Law and coorganizer of the Philadelphia session.
To John J. Lentini, arson investigation is a particularly troubling example. Much of the field has been “witchcraft that passes for science,” he said in Philadelphia. Lentini, a fire investigator, discussed the 1980 “Fire Investigation Handbook,” which codified unwarranted generalizations. It was published by the National Bureau of Standards, the agency that predated the National Institute of Standards & Technology. The book associated irregular cracks in glass—called crazed glass—with rapid heating, which suggests the use of fire accelerants. It also stated that narrow V-shaped char patterns on walls indicate fast-developing, hot fires. These myths, as Lentini called them, were once considered scientific fact in courtrooms. As an example, Lentini said, they were cited in the case of Cameron Todd Willingham, a Texas man executed in 2004 for setting an arson fire that almost certainly wasn’t arson.