Thanks for everyone for the replies, and prayers if you did.
I prayed and prayed for the pain and anger to go away. But during one prayer, I was asking God to make the anger and pain go away and put my heart at peace. I was telling God I was so mad at the shooter for what he did and I know it was wrong but I was hoping he gets the death penalty. About at that time I heard the words "what he DID" repeated in my head, and there was a strong emphasis on the word "did". And just like that all the anger was gone.
For some context, I've never had anything in my life where I was like that's definitely God, I haven't even had one that was maybe possibly God. But after this, I don't know.
I was able to mentally separate the person from the deed, I wasn't mad at the person, but the action. The sadness didn't go away, but the anger just vanished. As I lay there thinking and news story pops up on the TV that was showing all the childhood photos of the shooter. I started actually feeling bad for the kid. I'm not excusing the action at all, it's vile and heinous. But he was a good kid, had a good family, he just got radicalized in school and made a huge mistake that will more than likely cost him his life. It got me thinking about what Charlie would want done with his killer, and knowing how much Charlie loved everyone and valued life so much, I don't think he would want him killed. I honestly think Charlie would like to see him come back to God and go to heaven. And I pray that happens before he passes.