Disturbing surveillance video from Seattle captures a man using a high-tech device to unlock a minivan and steal what's inside.

Police across the country are using terms such as "mystery device," "mystery box" and "mystery gadget" to describe these improvised electronic devices that allow thieves to gain entry to vehicles.

Roger Morris, chiefs communications officer of the National Insurance Crime Bureau, said on "Fox and Friends" that there are a variety of such devices available for only $100 or so.

He explained that these mystery boxes can jam or mock a vehicle's keyless entry frequency - either by "code-grabbing" or simply by simulating a keypad.

"The important thing is they may be able to open the car, but we have no evidence that they are able to start the car," Morris said.

He noted that manually locking your car and keeping your keys on you can help prevent this. Also, don't leave valuables, a garage door opener or car registration information in plain sight, and park in a safe, well-lit area.

"If they're going to get it, they're going to get it," Morris said. "These folks are professional and they're always trying to beat the system."

"But make it as difficult as possible. Don't hand it over to them."

Watch the clip above.