Imagine locking your car at night and waking up to find someone has still gotten in to steal your stuff, and done it without breaking a window or jimmying a lock.

Neighbors suspect someone is doing just that in the prosperous Northwest D.C. neighborhood of Spring Valley. Someone got into at least a half dozen cars on Saturday without any sign of forced entry. A half dozen or so other cars were also broken into in the neighborhood the weekend before last.

D.C. police are investigating whether the suspect(s) used a device that amplifies the signal from your key fob, even if it’s inside your house, to open the locks. An even more sophisticated device can snag the signal from inside your pocket and mimic it to open your car, even start it and drive away.

So what do you do? It sounds a little wacky, but experts say you might want to wrap your key fob in aluminum foil when you’re not using it. Or put it in your microwave or freezer. All those things will help dampen the signal.

Auto manufacturers say they’re aware of the problem and they’re working on a fix.