I know of three on FR (two personally known to me). They were caught up in the child-abuse witchhunt of the 80s.
Part of the problem is people on both sides of the aisle pushing falsehoods. Here in Michigan John Conyers has repeatedly stated that people with felony records are denied the right to vote. It's a lie and he knows it's a lie. He wants people in prison, jail, on parole, or probation voting and that's a horrible idea.