they were known to get into a lot of fights due to his jealousy and controlling behavior (which is something I, personally, have never noticed before)

he always just said 'Oh Ive dated a girl here and there, but it never lasted for long' (which is a lie, since the articles state that they were a couple for 3 1/2 years).

Just so you know, lying is a controlling behavior. You didn't meet him through friends or a co-worker. You met him as a total stranger at a bar. I'm not sure if you're aware but a lot of serial killers or violent people are very charismatic. They don't get nervous because everything is a game. It's artificial. You met someone who was a prime suspect in a young woman's disappearance in a bar and are now dating him to the point where you call him boyfriend. If I had to guess, he's almost too charismatic?

Here's what bugs me. If I'm this guy and I'm innocent, I'm definitely not bringing this up on the first date. However, if the relationship progresses to the next stage I would sit you down and have a serious talk. "This is what I've been accused of. This is why those people said those things. I didn't want to bring it up on the first date but if we're taking this relationship further then I want to be completely honest with you. If you want to leave, I understand. If you want to stay, I'll answer whatever you want." If you had asked about past relationships, as an innocent person I tell you as much of the truth as possible until I'm comfortable putting the whole thing out there. "I had a 3.5 year relationship. It ended. It's very complicated and I'm not comfortable talking about it. Maybe when we get to know each other better."

If I were him and guilty (and I admit I have engaged in extreme manipulation in the past) I would absolutely ignore telling you until you brought it up for two reasons. 1) It acts as a litmus test and weeds out those women with high enough self-esteem to leave. Low self-esteem women are both easier to manipulate (again, I used to be an asshole) and inflate the ego of the manipulator. 2) The longer you're together and you don't find out, the stronger that emotional bond will be and the more vulnerable you'll be. "Oh, well I've known him for X months. He couldn't have possibly done it." In fact, now that I think about it, 2 is already in effect:

"I've never noticed jealous or controlling behavior." Already you think you know the guy, don't you?

I can't tell you one way or another. If I were this guy I wouldn't bring it up on the 1st, 2nd, or even 3rd dates. But I'd definitely be as truthful as possible when you asked questions and I'd bring it up before progressing relationship. If you feel like giving it a shot, bring the issue up at a coffee shop. Watch his facial ticks. That should tell you what you need to know.