Who is responsible for the recent suicide of a Florida teen?

In a horrifying live streaming video, a Florida teenager committed suicide while most people in a chat room watching him egged him on to go through with it. Is this something that could have been stopped? How? Who should have stopped this? Or was there nothing that could have been done to help this person before he did this live on the Internet. Should there be some law enforcement so this type of thing does not happen again?