Lynchings: By State and Race, 1882-1968
The National Registry of Exonerations has recorded 1,792 cases since 1989 of people who were convicted, then found to be innocent. Some of them were in prison for decades. Some were not exonerated until after they died in prison.
fake hate crimes: a database of hate crime hoaxes in the usa
False rape accusations: Why must we pretend they never happen?
Earlier: The Necktie Party, a short comic