One that has been doing teh rounds recently, is that Freddie Mills was the serial killer Jack the Stripper. I don't see it as having a shred of credibility of course.
Actually he died after slipping and hitting his head by a pool while doing a bit of rough-housing with some friends
Joey giambra allegedly had to hot-tail it out of the arena , still in his boxing gear, along with his corner-men after beating joey giardello in their 3rd fight because he was supposed to lose. He said it was some low level hood that was trying to put the fix in without the mobs blessing. He said had it been them he would have been in some real s**t.