Bicycle detail

I have a Black Trek 7.1 FX with a Bontrager bike rack on the back and commuter lights on the front and back.
I left my bicycle locked at the Salt Lake Public library while I studied and last saw it when I came back from lunch at 3pm. When I left to go home, I noticed that it was gone, so I talked to security and they checked the cameras and saw that it was stolen at approximately 3:17 p.m. (time I noticed approx 7:00). I had locked the bike to the rake with a flexible long lock. When I looked at the footage, it seemed like they just took it straight off, so I'm not sure how they did that unless something was wrong with the lock or it had already been cut beforehand.
Nevertheless, security has a photo of the person who stole the bike as well as footage of the man taking it. However, i was not allowed to get it directly, so the contact info for that is in the police report.