stolen 2014 Diamondback Clarity

My bike was stolen inside my apartment building in Lincoln Park. I have stored my bike inside a locked storage/ utility room here for 11 months and now it has gone missing. There is a padlock to enter the utility room, which the maintenance guy has given permission for myself and roommate to store our bikes in. We are the only 2 who store our bikes in it, thus emphasizing no other tenants have access or the code to enter this room because they dont need too. But this morning I entered the room and my bike has gone missing, while my roommates bike sits in his usual spot. Meaning my bike has gone missing because it was an expensive and in very good condition bike. Either someone in the apartment has taken it, or a worker who was working on the apartment has stolen it when they had access to the utility room for tools, other projects, etc. There is no other explanation because it is inside an apartment building and in order to get inside you would need a key to enter our apartment building, and have to know the lock code to the pad-lock.