My bike was stolen out of our 3 flat apartment bldg which we rent and just moved into Dec 2019. We know another tenant left the back door of our bldg not completely shut as there was no forced entry. Bike was on our enclosed porch on the 3rd floor. Our Kitchen door was locked and this opens onto the enclosed porch. Went to bed at 11pm on 14 July 2019- woke up at 5:30am 15 July 2019 to discover that the bike was gone. There is a sea of opportunists in our neighborhood trying every which way to find a compromised access into anyone's residence, single or shared. Of the 3 floors (3 units only, so not a large bldg) after entering the thieves came up all three floors looking for easily accessible and expensive items; my bike was the best item of all three floors. Aftermath is i saw the backyard gate wide open (it does not have a lock and is a chain link, so anyone can see into the yard.) with a neighbor tenant's items strewn against the back of our bldg. We could only surmise the door was left ajar either fully or minimally, as i have found previously to be our neighbor tenant's unfortunate habit.