Suicide Thoughts Always Caused By Thought Mismanagement

Just yesterday I discovered a man online who was begging for help due to thoughts of suicide. As myself years ago I had experienced the same and was talked out of destroying myself. Since then I have talked over 15 people out of suicide. I attempted to make friends with and talk the lonely man into better trains of thought. He was wondering why people abandoned him and he had no love from a Miss Right! I got to get him to open up to discover why all of his lonliness and what's causing the result of suicide thoughts! The man promoted violence/overthrowing the US Government/fighting police...need I elaborate further! I tried to kindly point out these anti-social behavior/talk was probably the cause of his problems! He got hostile @ me and actually rejected my suggestion of seeking therapy! I don't know what else to do with a man like this except to point out he's heading to prison if isn't mindful of his behavior and I just left him alone!  What are we to do with such people? Maybe merely "plant the seed" in his/her mind that there are severe punishments from acts of violence and that on the other side there is loving help from therapists. He made no specific threats nor did I know his address, otherwise I was going to inform police of a potentially dangerous, derranged man! With my conversation with him was all I could do! Lord help him!