There are a number of threads at the moment about murderers, the death penalty, and being later found innocent.
Has there been anyone who was convicted of being a mass murderer who was later exhonorated? We’ll allow the definition of ‘mass’ to vary as you see fit.
References:
Henry Lee Lucas was convicted of 11 murders and sentenced to death in Texas for the murder of a woman identified only as “Orange Socks.” He confessed to hundreds of other murders and later recanted all of his confessions. It was eventually determined that there was little or no evidence tying him to the Orange Socks murder. His sentence was commuted to life in prison and he died there.
Not quite what the OP is asking but close enough and IMHO an interesting example.
The Birmingham Six were convicted of murdering 21 people in a single explosion. They were found to be innocent 16 years later.
But I believe there is still evidence that he was actually involved with a couple murders, if not the hundreds he originally claimed. IIRC, the guy who hosts “America’s Most Wanted” believes that Lucas and his parter in crime Otis Toole were the ones who killed his son Adam (kid with the baseball bat, in the famous picture).
I think there’s no dispute that Lucas killed (IIRC) his Mom, the Christian shelter lady who took him & his girlfriend in, and his girlfriend. Also, I thought I read in a John Walsh book that Otis Toole finally admitted to killing Adam before he died in prison, but that he was acting alone.