Good dog!!! It's stunning when our loving, sweet housedogs show us that they really have a different "I mean business" sound when they perceive a real threat.
It's worth going by the police station to make a report, just so there's a record that someone has been lurking in your property. There's no telling who the police may be looking for that does that sort of thing, but it could be a datapoint that helps them realize someone is active in the area that they've been looking for.
Let all your neighbors know too -- the perp may try a different house without a dog, but the chance of catching him is higher if everyone collectively is looking out for him. See if you can get your neighbors all to join a site called Nextdoor Neighbor (nextdoor.com) -- it can create a local "neighborhood forum" where everyone can post anything going on, and it's a great way to track crime in real time. We know the instant someone sketchy shows up ringing doorbells pretending to sell fake products to see who's home and who isn't -- because people start posting, sometimes with pictures, tracking his progress, while waiting for the police, often with a description of the car and license plate. That kind of engagement makes a neighborhood very inhospitable to criminals. (I think once you set it up, you can send out electronic invites to everyone whose email address you have in the neighborhood, and they can then invite others that they know, and so on. It's usually done by a HOA, but I think anyone can do it.)