Guy knocking on door for the past 4 days

I am living alone in an apartment and there is a guy that keeps ringing the doorbell. At first I thought it may be one of those scammers since they tried the same thing on my next door neighbour but now I’m not so sure. The past 4 days the same guy keeps ringing the doorbell with today having him poke his head through the toilet windows asking if anyone is there. I saw this through the intercom recorder thing. He also aggressively knocked. I don’t know if I should just open the door to see what they want or ignore it and hope it stops eventually.

Update: thanks for all the replies, on my way to get groceries I saw that he had kicked the cockroach black cap trap down the stairs which has been there for weeks. I will not be opening the door.

by pickingstine