There is a sad story about a wrongly convicted man named Bill Dillon, who spent 27 years in a Florida prison for a heinous murder he did not commit.  He was only 21 years old at the time of the murder. Dog handler John Preston testified in court that he and his scent-tracking German shepherd connected Dillon to the killer’s bloody T-shirt. Preston said his dog, Harass 2, even tracked Dillon’s scent repeatedly in later tests.

Eventually, Dillon was convicted partly because of Preston and his track dog Harrass2. 

Preston was discredited in 1984, after a Florida judge who had become suspicious of Preston set up his own test for Harrass 2. The dog failed terribly.

Documents obtained by CNN show he could not even follow a scent for 100 feet. The judge determined the dog could track successfully only when his handler had advance knowledge of the case.

Dillon thinks Preston and his scent-tracking dog were part of a larger conspiracy.

“Preston could lead the dog to the suspect or the evidence,” alleges Dillon, but “any cases that were weak, not good enough to go to the jury, they [the prosecution] fed Preston information, paid him good money to come and lie.”

Florida’s Attorney General told CNN it is not aware of any evidence of a conspiracy involving John Preston and his dog.

Though Preston was discredited, Florida never reviewed cases on which he’d testified . And nobody ever told Dillon — who sat in prison another 20 years before he found out. It wasn’t until 2006 that he heard Preston was a fake.

Florida’s Innocence Project believes dozens of inmates around the country may have been wrongly convicted as a result of John Preston and his dog. It is calling for an investigation of those cases. Meanwhile, Preston, the dog’s handler, died. He was never charged with a crime.

A FLORIDA TODAY report on Sunday found more than 15 cases where the state or Brevard County law enforcement agencies used Preston. In one case, that of confessed serial killer Gerald Stano, Preston claimed his dog could track an 81/2-year-old scent. He was also used in cases against Juan Ramos and Wilton Dedge — both of whom have been released from prison after being exonerated.

In Dillon’s case, Preston testified that his dog tracked Dillon’s scent from a wadded up piece of paper to Dillon and to a bloody yellow T-shirt prosecutors say was worn by the killer. But last year DNA testing on sweat stains on the collar and inside the armpit areas of the shirt showed someone else’s DNA and not Dillon’s.

“Do you feel Preston put you into prison?” Kaye asked.

“Yes,” Dillon said. “Yes I do.”