Bf is a murderer😭

Before I get into this post if you are gonna judge me please leave now. Okay so a few years ago probably 2 I dated this boy for about a year basically he was trouble he was always getting into fights and things but I have daddy issues so I didn’t care as long as he gave me attention well I ended up realizing how toxic he was and tried to break up w him and he threatened to kill himself so I just cut everything off right then we’ll a few months ago his mom died and I told him I was sorry and hoped he was doing well and he tried to flirt with me so I cut it off once again well not to long ago I heard he got arrested and I was in shock bc he was arrested for murdering a 17 year old boy in his home. We don’t know for sure what it was over but most people think it was gang related. He got charged with capitol murder. I am 15 years old he is 17. I’ve been struggling with blaming myself for not telling anyone he was crazy and I feel that I need to apologize to the family of the victim what should I do please help