When Bill Dillon was convicted of murder in 1981, DNA testing wasn’t available. Instead, investigators and prosecutors relied on the testimony of John Preston and his supposedly infallible scent-tracking German-Shepherd, Harrass 2.
According to Preston, Harrass 2 repeatedly connected Dillon’s scent to the killer’s bloody t-shirt, was able to track Dillon from a paper he had touched, and even located him in a room where he was being held in the courthouse during his trial.
In fact, Harrass 2 wasn’t much of a tracker at all.
In 1984, a Florida judge became suspicious of Preston and his dog and set up a test; Harrass 2 failed miserably. He couldn’t track a scent more than 100 feet. It soon became obvious that the dog only appeared to track a scent when his handler, Preston, was with him. And apparently Preston could only lead the dog when he had been given his own lead by the prosecution.
That revelation, however, did Dillon no good. He spent another 20 years in prison before he even found out that Preston and Harrass 2 had been discredited. It wasn’t until 2007 that DNA testing proved that his DNA didn’t match that on the killer’s shirt.
Preston died last year and Florida’s Attorney General insists it’s not aware of any conspiracy involving the tracker and his dog. Preston was never charged with perjury or convicted of any crime.
How many other people were convicted based on Preston’s and Harrass 2’s evidence remains to be seen.