While the number of cars stolen in the U.S. has been slashed in half over the past 20 years, authorities are now seeing more break-ins using some sneaky high-tech tactics.

Two years ago, Michael Shin of Los Angeles captured of footage of a man opening his car holding just a backpack. Shin — who always locks his car — said the man had no break-in tools in hand.

“It’s just a little unnerving that they could so easily just walk into my car and pretty much without any recourse, without anybody really noticing,” Shin told CBS News.

While this kind of break-in has puzzled authorities in the past, insurance investigators now believe that criminals are remotely taking advantage of key fobs — those little authentication devices you use to access newer “keyless” models — to unlock and start cars with just the push of a button.

“You can’t stop this kind of theft right now,” Roger Morris of the National Insurance Crime Bureau (NICB) told CBS News.

Morris explained that these high-tech thieves use two devices to break into cars.