Noone here was present, its almost impossible to see what went down prior to the tasering by the video, and most of you are obviously unable to read the news story which may or may not be accurate.
According the the news story, he didn’t show his ID to the campus security and when they left to get police, he gathered his stuff and started leaving. The police showed up and grabbed him on the way out. On the legalities of what happened, I dont know who is at fault… I am not a lawyer or judge.
If my opinion was asked, I would say that it depends if it is against the LAW to be inside the library without an ID.