Bicycle detail

I spent the night in the Portland State University housing building Stephan Epler Hall and left my bike outside overnight secured to the green metal bike racks on the east side of the building. I saw it around 11:00 pm July 29 and it was gone the next morning July 30 before 07:30 am. I thought I secured it properly with an OnGuard U-lock around the frame and the rack and a cable through the front wheel but the cable had been cut through and the lock was still secured to the rack. Perhaps they cut through the frame but I may have also neglected to secure it properly.