Privacy issue (apartment) and I need some advice. Details inside?

As some of you may know, I rent an apartment in a 4 apartment old home. There are two apartments upstairs and two downstairs. I live upstairs. A new tenant moved in a month ago, a female (she lives below me). There is one vacant apartment downstairs, and there is one fellow across the hall from me. The guy across the hall is a young guy (in his mid 20’s) and his g/f is over a lot. I am pretty sure that this guy has a key to all of the apartments, as the landlord lives out of town (is too lazy to come in), and he has this guy looking after the place. The tenant shovels, puts out garbage and does other yard work.

Anyhow, I have noticed that since the tenant across the hall has been taking care of the outside,stuff in my apartment has been moved around a bit when I came home (I’m usually away on weekends). My bottles of booze on the fridge moved, and a few other personal items have been moved. I came home one day and the door was unlocked. I always lock it.

When I first started renting, my girlfriend and I noticed that someone was doing something with the ceiling in the bathroom and didn’t put the piece back into place. Wires above the shower were exposed. When talking to my landlord a few weeks later, I told him that I really lovde my place. That “it’s really cozy”. He said to me, “yeah, and I love the way that you have it decorated and your modern furniture”. I said “Oh?”, and then stumbling over his words, he said “yeah, I had to take care of something in there”. He is supposed to tell me ahead of time that he is going in.

I asked him if he gave the tenant across the hall has a key and he said no. He wondered if there was anything wrong.

Maybe, I am paranoid, but, perhaps, he did give the tenant a key (in case that he needs to get in there) and he doesn’t want to tell me. The tenant with the key is a young guy (with an obnoxious g/f) and perhaps they went into my apartment and were looking around at stuff.

Stuff was obviously moved.

What do you think? What should I do?

(I’m not leaving my dildos out anymore, haha!)