Occum's Razor.
You just summed up the situation perfectly and succinctly without using a single word more than necessary.
Going back to the pool of possibles.
He did 20 years in jail.
They were able to trace his childhood back to Queens, where he grew up.
He stood up him self.
He wasn’t a bad drug addict.
He wasn’t a bad alcoholic.
He wasn’t a degenerate gambler.
Seems like he couldn’t play the politics
He wasn’t a big earner
He didn’t want to kiss his capo’s ass.
