Dealing with the aftermath of a shooting

TW SHOOTING This is just a vent. I live in a town that recently experienced a shooting at a 4th of July parade (I'm not gonna say the name, but you can probably figure it out). I was lucky enough to have not gone to the parade, but my father owns a business that the shooter spent a lot of time at. I had always felt uncomfortable around him and had told my father multiple times that I felt like he was a threat to others, but my dad told me he was working on himself and that I shouldn't judge him. Now i feel insanely guilty for not talking more about how i felt. Listening to any news or discussion of the shooting gives me panic attacks. I feel so unsafe and I don't trust anyone anymore.