Some 20 years ago when I was in high school my friends and I noticed a stranger climbing into a nearby building that was under construction. Being the idiots that we were, we surrounded the building so he couldn't escape and then called the cops. They did eventually come and timidly peek inside where the guy was but didn't find him. He was definitely still there, we saw him leave later, the cops just didn't try at all. While the cops were there a police helicopter flew over and illuminated the whole street. I think that's when they reported sighting us idiots to the cops on the ground because soon after they came out and told us there was nothing there and to forget it and go home.
Turns out the guy was just an anti-semitic vandal intent on spraying dumb stuff on the walls and not there to steal expensive construction equipment.