Bicycle detail

Wen outside to take trash out late one night. I believe they were trying to take it then. When I opened my back door i saw someone run away from under the stairwell. I went to make sure my bike was locked up good. They had to come back with bolt cutters or something to break the lock. In the morning when i went outside, my bike and lock was gone. I bought the bike from my roomate, I never registered it. I dont know much about bikes, so I know only the obvious features about it.