How can I cope with this?

In 2004 I bought a pitbull pup for Christmas with my own money, I was 11 years old. I raised him and loved him and he got really big so we kept him outside in our backyard. We have a fence. It was 2007 at the time and my family and I had gone out, when we came back the neighbor told us animal control took my dog cause he got out. We went to go get him back and supposedly some kids were by our fence provoking him with a puppy and hitting him with a stick to get out and my dog "Buddy" made a hole and got out and scratched a kid. Since that year we had not put him his yearly rabies shot yet, they didn't want to give him back. I didn't understand what was going on I just wanted Buddy back, I saw him in a cage at the animal control thing his fur was grey (he was white with brown spots) and he couldn't stand up clearly he was drugged but we came home without him, I knew they had killed him. I hated those kids, I know they did it on purpose cause I knew them from school. They are rich kids that always get what they want and I want to kill them. I thought that feeling of taking revenge would go away throughout the years but I can't get over it, I need closure I need revenge. I don't know what to do, I want to find those guys and beat the **** out of them for what they did. At least that way I would feel a bit better. Don't tell me I need to seek help, I'm not crazy I've just been sad for 5 years. I'm over Buddy's death that's not the problem, it's those kids (teens by now) I know they are still alive and I'm mad at that >:C