An increasing number of thieves are using some kind of a high-tech device that apparently sends out an electronic signal to open the keyless entry systems used to lock new cars.

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"There is some indication that there are some devices out there that are somehow, and we're not sure exactly how they work, in some way get the computer in the car to unlock the door," said Roger Morris, chief communications officer for the National Insurance Crime Bureau.

Morris said no one is sure "whether it's some kind of a radio transmission, a frequency transmission, whatever, and it's been an ongoing discussion in the law enforcement community and the insurance community as to what's going on with these. It's becoming fairly clear that some of these devices are out there. There's a lot of them being touted on the Internet."

People need to understand, Morris said, that while today's cars have very advanced anti-theft technology built into them, there are always thieves that are hard at work, staying one step ahead, as they look for ways to beat the system.

The message to drivers is, according to Morris, "Don't leave valuables in the car, don't leave your keys in the car, don't leave a phone showing, sitting out on the seat. You don't want to encourage crooks by leaving stuff in your car in plain sight. We've made great strides, but if somebody really has the wherewithal to do this, it's going to be very difficult to stop them."

Morris said the device being used to open keyless entry systems cannot start the vehicle, so it's not being used to steal the car itself, just to allow crooks to get what is inside.