Bicycle detail

I left my bike beside the Donadeo Innovation Centre for Engineering building at University of Alberta in a bicycle parking area around 2:40 pm and went to Mechanical engineering building. I locked my bike with a black cable 4 digit combination lock equipped with LED light . The brand of lock was rolson and the approximate value of it was about 13$. There was a lot of bikes there when I parked mine and I also saw a homeless guy around there. He was about 40-50 years old and had facial hair, I think he was wearing a dark green jacket. I am not sure if he stole the bikes but he was the only nont student person that I saw then. When I came back around 6:30 pm It was gone and the steel rack was relocated. The lock was also gone. I went straight to the protective services at University of Alberta and report the incident to an officer. I do not know if the area had security cameras. My bike was a Northrock Mountain bike. The color was matt black with orange text written on it. It had fat tires. Unfortunately I do not have the Serial number under the bike but there was a sticker next to the warning notes on the top tube of the bike with the following information: ITM./ART. 1495021 and serial number of 850018990325. I do have the purchase receipt and I bought it from costco.