Surveillance video from Long Beach showed a man approaching a car with a device in his hand and it disables the car alarm and unlocks the car door.
In the video it worked on Mazdas and Acuras, but didn't give the thieves access to a Ford or a Cadillac. Police say they've never seen anything like it.
"We've shown this video to experts in the field and everybody right now, they don't know what it is," said Long Beach Police Det. Joe Starbird.
Long Beach police say they're working with law enforcement agencies across the country as well as vehicle manufacturers to identify the technology being used.