Stephan Cowans
On May 30th, 1997, a Boston police officer was shot with his own service weapon following a short tussle with the assailant, who then shot at another individual who was watching from a second floor window. The shooter then forcibly entered another home where he drank water from a glass in the kitchen.
A picture of Stephan Cowans, a 27-year-old with a record of petty theft, was shown to both the officer and two residents, including the one whose home the assailant entered. Only the injured officer identified Cowans in the photo array. Regardless, Cowans was indicted and charged with intent to murder, possession of a firearm, home invasion, and assault.
In court, two fingerprint analysts testified that the thumbprint lifted from the glass of water belonged to Cowans. Based largely on the testimonies of these expert witnesses, the jury found Cowans guilty and he was sentenced to 35 to 50 years in prison.
Despite the seemingly impenetrable evidence against him, Cowans continued to uphold his claim of innocence throughout his sentence. He eventually received support from the New England Innocence Project, where DNA testing of a sweatshirt and baseball cap also recovered from the scene were used to exclude him as a suspect. After six years spent behind bars, Stephan Cowans was finally released from prison.
However, the question remains:
If Cowans was not the one who committed these crimes, then why was his thumbprint found at the scene?
His story represents a case where the flaws of fingerprinting—the seemingly unique, unmistakeable, and infallible forensic science—were exposed.
Unlike the television representations of fingerprint analysis, there exists no completely objective algorithm that can flawlessly match a crime scene print to a suspect.
35-50 years
June 30, 1998
February 2, 2004
6
Fingerprint Analysis
Charges:
Sentence:
Convicted:
Exonerated:
Years Incarcerated:
Contributing Forensic Discipline:
Case Summary
Armed Assault w/ Intent to Murder, Home Invasion, Assault and Battery by means of a Dangerous Weapon, Armed Robbery, Assault and Battery on a Police Officer, Assault by means of a Dangerous Weapon, Unlicensed Possession of a Firearm
This discipline is still very subjective and the conclusion of whether two prints match largely rests on the opinion of an examiner, not carefully curated and impeccable standards and methodologies. Despite the subjectivity of analysis, many judges don’t even require fingerprint experts to be certified.
In court, experts often make claims that they are sure to a “reasonable degree of scientific certainty” that two prints match. However, without any proper error rates, there is no way to determine what this claim means, making it difficult for the trier of fact to assess the weight of each testimony.
Only two properly designed studies have attempted to determine the false positive rates of fingerprint analysis or, the chance that the wrong individual could be matched with the crime scene print, like in Cowans’ case. Even these two studies, however, do little more than illustrate the need for more research to be conducted on the validity of this forensic science discipline: the studies vary drastically from a 1 in 18 error rate to a 1 in 306 in another study. Transparency needs to be improved between witnesses, juries, and judges to ensure that there is a mutual understanding of every analysis presented in court to protect against overconfidence and future wrongful convictions.
Although many exonerees do not receive any compensation for a wrongful conviction, Cowans received a 3.2 million dollar settlement for the six years he spent in prison. However, less than three years later, he was found shot to death in his home. His case remains unsolved.