+1 on everything Dagny has posted.

We have had very similar advice from the Sheriff's Department in Loudoun County VA, (no County police there) and here in Anne Arundel County, MD.

It can't be stressed enough to get everyone in the neighborhood to call the police if the see something suspicious, something out of place, or even just something that makes them uncomfortable. Don't be afraid that it is not important and that you are wasting police time. Our police keep telling us they want us to do that.

Also, it turns out that the more calls that come in from an area causes the scheduling of more police patrols. This is what you want.

Thus, I have been known to call in, for example, a car parked in front of my house at 3 AM, lights off, engine running. . .and had a patrol car pull up behind it about 5 min. later. . . never did find out what was going on. . .

And my neighbor has called about "door to door" salesmen. Her you need a license for that, and he didn't.