A cop was shot and killed. Troy Davis was charged and convicted with the murder of the cop. There was a pair of shorts that was taken from his house without a warrant so it was not allowed in court. There was no murder weapon, but the bullet casings found at the scene of the crime was the same as the casings of another shooting Davis was charged of, but not convicted with. So basically it all relied on eyewitness testimony. There were 9 non-police witnesses and he was found guilty. This was 20 years ago.
7 of the 9 witnesses have changed their testimony. Some of them said it was another guy, and some of them were saying the cops forced them into accusing Troy.
Much of the evidence that they relied upon has either been wrong, or have been questionable.
There was another guy name Sylvester "Redd" Coles who owned a gun matching the one that killed the officer. He also is the person who went to the cops and 'turned in' Davis.