In recent months, law enforcement corporations throughout the U.S. have been receiving reports regarding vehicle thefts using a “mysterious device.”

“The mystery device named  Relay Attack works through a modem that hacks, or copies, the signal and code emitted by a vehicle’s keyless entry remote, allowing thieves  to use the device to open doors and start the vehicles,” said Roger Morris, NCIB Chief Communications Officer.

When a driver exits their vehicle, and locks it with a remote device, the thief uses the Relay Attack device from a few feet away to capture the code emitted by the driver’s remote to the vehicle. The code is then relayed to a secondary box that is placed beside the handle, tricking the car’s network into thinking it is receiving the original signal, thus unlocking the door.

The NCIB tested 35 different cars, minivans, SUVs and pick-up trucks and were able to open 19 of those vehicles using the Relay Attack unit.

This device works only on newer vehicles that have a keyless remote and a push-button start.

NCIB investigators found that, in most cases, the crime was perpetrated by at least two people, one to operate the device and the other to serve as a lookout. The Bureau released a series of videos, sent in by different businesses, with security camera footage showing how these thieves work.

Despite its effectiveness, this method is not widespread in use as it has a high barrier of entry; these devices can only be bought online, mostly from European sellers, and cost anywhere from $2,000 to $60,000. As a result, authorities warn that this makes thieves with the device them even more dangerous, given that once thieves invest in the device will go to greater lengths to recover their investment.

The NCIB obtained a Relay Attack unit from an unidentified company, allegedly from Europe, prior to announcing the unmasking of the “mystery device.” The NCIB describes the Relay attack as a “low-power threat evaluation unit aimed at testing cars’ vulnerability to thieves.”