I had a guy in my class kill himself earlier this year. It wasn't because of bullying, he was one of the most popular people in school. We were in the same group in art class, so I did talk to him often.
All I know is he was heavily into drugs and the like. Some rumors went around about how he ended up getting into trouble with the wrong people, and was being threatened. Don't know if it's true, but I do know he left work one afternoon, went out for a smoke, left, texted a co-worker saying if he didn't return the boss would know why, and was found later that day, after people went looking for him(he disappeared from work after all), and he was dead. It was deemed a spur of the moment thing, no long standing reason for him to kill himself, but still tragic.