You want to help her, yet all you can do is talk about how much of an asshole he is, which I'm sure she wouldn't appreciate. Also, if the post is lacking context then that's your fault. We give advice based off the information given. It's your responsibility to provide the details, and if something gets left out, then that's on you.

Okay. So you knew him personally and he did a lot of stuff wrong. What the fuck does that matter now? He is dead. She is upset about it. No matter what he did or why he did it, he is now dead, and your girlfriend is mourning. So stop ragging on the dude. You have to face a tough thing here. You need to sit down and have a serious talk and ask her if she is in a good place to be a relationship. Don't accuse her of loving him more than you, don't accuse her of thinking about him more than you, do not bring up any of that jealous bullshit. Just ask her if she is okay, and if she can handle being in a relationship right now. That's all. Set aside all your anger and reservations for her feelings.