Five Years Later: Wilton Dedge and Dog Scent Evidence


This week marks the fifth anniversary of the day Wilton Dedge walked out of a Florida prison into the arms of his parents. In 1982, he was convicted of a rape he didn’t commit and sentenced to life in prison. He would serve 19 years before DNA testing obtained by the Innocence Project conclusively proved his innocence in 2001. The state then opposed Dedge’s release on procedural grounds and he was not freed for another three years.

In addition to an eyewitness misidentification and unreliable testimony by a forensic hair analyst, unvalidated dog-scent evidence played a large role in Dedge’s first conviction in 1982. At trial, a “scent-tracking expert” named John Preston testified that his dog, “Harass 2,” sniffed an item with Dedge's scent and then allegedly alerted Preston of the same scent in the victim's house. Although Dedge’s conviction was overturned in 1983, the appeals court nevertheless asserted that the dog’s scent identification was persuasive. Mainly based on the testimony of a known jailhouse snitch, Dedge was reconvicted after a second trial in 1984.

Despite not being a validated science, dog-scent identifications and lineups have continued to be permitted at trial and have been a contributing factor in other wrongful convictions later overturned by DNA testing. The case of another recent Florida exoneree, William Dillon, also hinged on the testimony of the same so-called expert, John Preston, who died in 2008. In the course of his career, Preston convinced over one hundred juries in Brevard County, Florida, and around the country of his dog’s ability to track scents, even if those scents were underwater or it had been more than a week since the crime had occurred. Other scent experts have countered that such scent identifications are impossible.

Responding last month to public outrage and concern that others are still wrongly jailed based on the fraudulent dog scent testimony, Florida State Attorney Norman Wolfinger ordered a review of murder and sexual battery cases in which Preston testified. Florida Today wrote that an

in-house review of the cases won’t be reliable, and the Innocence Project of Florida has called for an independent investigation


Unvalidated forensic science such as dog scent evidence has been involved in about half of the 241 wrongful convictions overturned to date. The Innocence Project supports the creation of the National Institute of Forensic Science, a federal agency to support and oversee forensics to prevent wrongful convictions and ensure public safety. Thousands of people have joined the campaign by signing the Just Science Coalition’s petition calling for federal forensic oversight.

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Other Exonerations


Ryan Matthews

, Louisiana (Served 5 years, Exonerated 8/9/2004)


Gary Dotson

, Illinois (Served 10 years, Exonerated 08/14/1989)


Roy Criner

, Texas (Served 10 years, Exonerated 08/15/2000)

Eduardo Velasquez

, Massachusetts (Served 12.5 years, Exonerated 08/15/2001)

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Ron Argo December 26, 2019 at 4:52 pm Reply   

2 million is not enough

We've helped free more than 240 innocent people from prison. Support our work to strengthen and advance the innocence movement.