Is there any way to file a police report to ensure an arrest?

I have to ensure an arrest. I feel as though I am in physical danger. The person that I have to file the report on is caught up in drug dealing and drug abuse. Specifically, he is dealing marijuana, shrooms, and DMT among other things. He is engaging in sexual activity with minors as well as dealing drugs to them. The thing is that if I call the police and they just go talk to him, he'll know exactly who called them and I will be in a world of real danger because he is violent and has gang ties as well. It gets complicated. Basically, what evidence do I need to ensure his arrest and what information should I include in the report? I intend to file the report anonymously, is that an option? What do I need in order to ensure his arrest and a trial with an appropriate sentence?