Want to hear about a weird situation I have, read this thread. I'm confused/curious/weirded out by it

So here's the scene: I live in the hipster part of the city, directly off a Main Street. My side is houses, the other side a gated condo community. Decent neighborhood.

So the night a few nights ago I got home not too late, around 8 or 9 and noticed a dude smoking a cigarette leaning up against a small wooden fence by the sidewalk. No big deal, right? I lock my car, which he is roughly ten feet from, and go inside my house, another 25 feet or less away.

I FaceTime my lady friend, and now fast forward 2 or 3 hours to 1am.

I look outside and the guy is still there. Sometimes leaning against the fence, other times pacing, and occasionally he walks across the street. I'm still on the phone with my lady relaying her all this.. Another half hour passes and I think it's straight weird.

So I call the cops, tell them what I've seen, then wait. Two cars roll up ten minutes later, one cop looks around with the flashlight, the other cop talks to the guy. The guy hands the cops some papers, and a few minutes later, the cops leave, and the dudes stays there.

I go to bed, still confused.

I see him there the next two nights and try to just not think about it.

Then tonight I'm home and see him again, and my curiosity gets the best of me.

I keep tabs on him the next few hours. He chain smokes, has snacks that he eats, and a bottle of something to drink.

I want to see how shy this guy is, So I grab a couple cigarettes and go sit on my front steps to "smoke".. He immediately goes back to leaning on the fence and doesn't move or make any noise.

I light up the second cigarette. Take my time, and eventually he grabs his plastic bag, and walks by me and past the next building out of sight. I wait a few more minutes then go inside. Before I could even get my jacket off and look outside again, he was back.

Over the next hour, he crosses the street several times, walks up to the gated condo community and squats down like he's straining to see something. And he does this from several different angles. Then He'll eventually make his way back to his post 25 ft from my doorstep.

So now it's 3am and he's still there. Crossing the street, chain smoking, and pacing up and down the sidewalk, but never venturing very far.

WHAT DO I DO???? This is just weird guys. Do I call the cops again? If I call to try to find out why they didn't make the guy leave, would they tell me? Should I try to talk to the guy? what do you think he is? Or is doing???