Can I get in trouble for confronting my neighbor because of his trash and he's a cop?

My neighbor's trash has been ending up in my yard for the last three months. After about the the 3rd time I discovered who owns the trash because their junk mail was in it. After I cleaned everything up and threw it away in the trash can, I left a nice note in their mailbox, I didn't hear anything. It happened again, with their mail inside, I bagged up the trash and took it to their house across the street, and left a not so nice note taped to the door along with their mail from the trash. There have been diapers and sanitary napkins in the trash. So it happened again today, this time they were home, I took the trash over there knocked on the door. First, he asked me how do you know it is our trash, and I replied with because it has your junk mail with your address on it. The neighbor claimed that there must be dogs dragging the trash out, I said there is no way that a dog coincidentally dragged your trash and yours only all the way across the street to my house, at least five times now, two of which were in the backyard. I told him that if it happened again, I was going to call the police. He responded with, "Well good, I am the police, now get of my property!." Obviously I didn't know he was a cop. I admitted to him that I left the note, because he asked before he told me he was the police. Now I'm wondering, did I do something illegal, is he going to have it out for me? Can I get in trouble?