Blacklimitedcoupe, I'm really sorry to hear about your break-in. The same thing happened to us 20 years ago this summer. Cleaned us out pretty good, but didn't get any of our car keys.
They returned about a month later (figured we had replaced everything they stole) but didn't realize we were at home. Took off as soon as I turned the outside light on.
I got their license # and called the SHERIFFS DEPT. but they said they were probably just turning around in my driveway. Our drive way goes up a steep hill and circles around behind our house and is 224' long. I told the dispatcher nobody pulls up to our garage at 10:00 PM at night just to turn around. So they sent out a car and took a report but that's as far as it got.
I did some investigating myself, and found out they lived near a friend of mine, and when I asked him how well he knew them, he said everybody in his neighborhood thought they were responsible for a string of break-ins that had been going on for some time where he lived. But of course nothing was ever proven.
Before the break-in we were getting a rash of hang up calls, so we started screening all our calls after that.
Needless to say, but change your locks, and maybe consider a security system. At the very least, put up some "phony" security signs.
Good Luck.