Please post links to those other articles. The only other account I've seen is from AP and only quotes the spokesperson for the cops.
I'm just going by the information presented. Based on what we have here. The cops are the ones who committed a crime.
"The CSO made an announcement that he would be checking for university identification. When a person, who was later identified as ... Tabatabainejad, refused to provide any identification, the CSO told him that if he refused to do so, he would have to leave the library.
"Since, after repeated requests, he would neither leave nor show identification, the CSO notified UCPD officers, who responded and asked Tabatabainejad to leave the premises multiple times. He continued to refuse. As the officers attempted to escort him out, he went limp and continued to refuse to cooperate with officers or leave the building.
Greenstein said Tabatabainejad encouraged others in the library to join his "resistance." She said a crowd gathered around the officers.
http://www.nbc4.tv/news/10325914/detail.html
And the student newspaper you are relying upon says "No university police officers were available to comment further about the incident as of 3 a.m. Wednesday, and no Community Service Officers who were on duty at the time could be reached."
And then provides an unsourced account of the incident followed by quotes from shocked students from the tail end of the incident. Were any students with a conflicting version not quoted? Did any of the quoted ones see the whole thing from beginning to end?