Years ago I worked at Dr. Smith's office. And I did exactly that I went through the trash and I did find an ID. After contacting the individual I found out that she had paid someone to clean trash out of her back shed. And they had disposed of it in that dumpster.

I would think build yourself a fence around it and put a locked gate on it that would surely help and perhaps a security light. They even have dumpster fencing that you can put around it. Or put a lid on it a chain around it were you can't open the lid unless it's unlocked. It's happening at night it's not happening during the daylight. It's a shame you have to go to those measures. Good fences make good neighbors I guess. I've had to make a huge investment and I don't have the money to spare just so my dogs can be safe in their own yard!