Lakeview homeowner Michael Shin parks on the street and says he always makes sure his doors are locked.
So when someone broke into his car last month, without any signs of damage, Shin was dumbfounded.
"I kept thinking, 'how did they gain access to my car if nothing was broken?'" he said.
Shin's new security system captured the crime. Just after 1 a.m., the camera snaps on as someone walks into the frame.
"He walks past my car, the dome light comes on, and he kind of stops in his tracks and walks right into the car," Shin said. "It's mindboggling how smart they are to build some sort of a device or an app, or something that just allows them to steal easily."
He put pictures of the crime in progress up online, and soon neighbors started reporting the same problem, finding their cars unlocked, belongings stolen with no damage.
Locksmith Bill Plasky specializes in car transponder technology.
"Honestly I've never seen anything like that," Plasky said.
He says most car thieves use brute force rather than just hoping they can crack a code.
"Maybe there's just someone out there that wants to get beyond this technology," said Plasky. "Because so many people think it's secure, 'oh I'm going to figure a way around it.'"
"It's quite possible that they already de-encrypted the code, they actually have the key of the car, so they can open it any time they want," said IIT professor Yang Xu.
Wireless signal experts say it's possible for someone to mimic the unlock signal car transmitters send, particularly in older cars, and trick the car's computer into opening the doors.
"We believe that this code grabbing technology was utilized and we are looking into it and investigating," said Andrew Schoeff of the Chicago Police. "It's kind of an elusive crime for us to report and even to take note of in the first place."
Chicago Police say most people who may have had their cars broken into this way just assume that they forgot to lock their doors, and they're still searching for this thief.
"I just don't feel safe with my car," Shinn said. "Somebody could be in there, they could go in there and take anything out of the car."
Wireless experts say that many newer cars have updated technology that changes key codes constantly so signals are harder to copy.
Unlocking cars is just one part of this problem. For cars that have proximity keys, keys that just have to be close to the car for it to turn on, thieves could boost or copy the signal to one of those, and steal the whole car.