(CHICAGO) -- Just after 1 o'clock one August night, a man calmly walked up to a locked car parked on a downtown Chicago street and within seconds -- without a key, without any force -- was sitting in the passenger's seat. If you witnessed it, you wouldn't think anything of it. It was just a man getting into his car.
Except it wasn't his car. It was someone else's, but the man had easily broken in and could now steal whatever he wanted. Thieves, it seems, have figured out a way to unlock cars equipped with security systems, all without so much as breaking a window or even jimmying a lock. While they are not actually stealing automobiles yet, they are able to steal belongings found inside locked cars.
That car in Chicago belongs to Michael Shin, who thought he was losing his mind when his sedan was robbed. Shin, after all, had locked the car, but now his belongings had been stolen with no sign of forced entry.
"I kept thinking, 'How did they gain access to my car if nothing was broken?'" he told ABC's Chicago station WLS-TV.
Fortunately for Shin, the answer was right there on his home security video, so he got to see how the robber had done it.
"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 told WLS. "It's mind-boggling how smart they are to build some sort of a device or an app or something that allows them to steal easily."
It wasn't only Shin's car that was robbed -- his neighbors' were, too. Wireless signal experts think some car thieves have cracked security codes, so they are able to send the same unlock signal that an owner's key transmitter uses.
"It's quite possible that they already decrypted the code, they actually have the key of the car, so they can open it any time they want," Xang Xiu, a professor at the Illinois Institute of Technology, told WLS.
That is what Chicago police believe too.
"We believe that this code-grabbing technology was utilized and we are looking into it and investigating," the Chicago Police Department's Andrew Schoeff told WLS.
The technology that keyless entry systems use has become much more complicated since 2010 and now changes the codes on a regular basis, but for systems that were built before then, it's a different story. And that has left locksmiths like Bill Plasky feeling dumbfounded at how thieves are now exploiting outdated systems to open cars like Shin's.
"Honestly," said Plasky, "I've never seen anything like that."
Copyright 2012 ABC News Radio