I'm in the same general area as the OP. Legally, he's fine. If he gets in trouble w/ the po-po, it's because he decided to be nice and not ventilate the perps.
Just to give you an idea of how things are, a few weeks ago our neighbor's burglar alarm went off during the day. The hubby called the cops and was out with the dogs waiting on his cell phone for the cops to show up, and keeping an eye on the house. One deputy arrives, looks at the hubby and our big GSD, tells hubby to put a leash on the dog and walk around the neighbor's house with him as his backup is fifteen minutes away. The GSD in question is a 100# love-lush, but a goblin wouldn't necessarily know that.