I knew a lawyer who told us about a case his wife (a prosecutor) worked on where a man was being tried for armed robbery. He robbed a guy at gunpoint while standing under a street light and without any sort of disguise, so his face was seen clear as day. When the perpetrator was arrested less than an hour later, the police found the victim's belongings (as well as the weapon the victim had described) in trunk of the suspect's car.

The case went to trial. The prosecution felt it was an open-shut case.

The jury acquitted.

My teacher's wife asked the jury why they acquitted when the evidence seemed so strong.

The jury said the prosecution hadn't even raised the (in their mind, very real) possibility that the police officer on the scene planted all that evidence in the suspect's car to frame him. This was in an urban part of NY State, by the way.

So glad I got out of that state, and I have little sympathy for the blight that continually befalls the ethnic community the suspect and the jury belonged to; after hearing about that case (and other national events since then, obviously) I now realize they bring it largely upon themselves.