Dallying, this guy's email to you was a big page of smoke and mirrors. Is he intelligent? Sure. But functional 36 year old men aren't paranoid about former mafia associates and aren't violent when drunk.
In fact most healthy, well-adjusted 36 year old men are tucking their kids into bed - or at least dating women within shooting distance of their age-group. That's not to take anything away from you - you're a seriously smart cookie for breaking up with him and I bet you have everything in the world going for you.
To be frank, his email raised the hairs on the back of my neck. You've had some great 'between the lines' feedback and what struck me most was the 'me, me, me, me, I' of it all. He quotes the DSM - your sister is a psychiatric med student, right? Most civilians wouldn't know what the DSM is and that makes me wonder whether he hasn't been diagnosed with something more serious than depression at some point. His email is totally narcissistic.
All of which is moot because your gut has already told you that there's something fishy. There is. His running into you is pretty suspicious. And with these kinds of guys, when you finally do make a break and mean it, you really can't be too careful. I agree with the run don't walk advice - and I'd also rally my friends and family around me and keep them in the loop as much as possible.
Hugs,
SL.