I gather that you either a) don't want the bike or b) are physically unable to retrieve it.
You are acting like a spectator here. You ARE involved. By doing nothing, you are creating trouble for others, and failing to create a good. They must go through an extensive process to protect the rights of an owner they don't know who even is.
What you should do, is to send a paper letter to the landlord at that complex.
You may have a bicycle at Location Here inside Apartment Complex Name Here.
I am the owner of the bicycle. I had to leave the region, and I had to leave the bicycle behind. I cannot come back and claim it.
Perhaps you know someone who could use a bicycle. Please give the bicycle to them, or dispose of it as you see fit. Here is the key to the lock.
Why a paper letter? Because you can't email a key! If you sent an email and key separately, they'd get confused. Plus, the signature on paper is legally binding, so they don't have to worry about it being a trick.
Tape the physical key to a piece of paper, to keep it from rattling around and chewing a hole in the envelope. (it could be the paper the letter is written on, note that a printout of a Word document is fine).
Paper letters have gone out of style, I know; you can work out how to send them, but an older person will help you do that faster, since well, we used to do everything that way.
Now if you do want the bicycle, that gets harder. You will have to have one of your roommates give a key to someone who can retrieve it for you and store it for you. And you/they may need to coordinate with the landlord to even get access to it / find out if it's still there. This is probably a waste of your time.