By Steven Graves

OAK LAWN, Ill. (CBS) — Would-be thieves targeting parked cars in the suburbs.

Only on 2: There’s video showing exactly how they do it. The suspects only getting away with a picture.

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CBS 2’s Steven Graves had a warning for car owners Thursday.

Monday around 4:15 in the morning…

“All of a sudden boom, boom, boom.”

Six booms to be exact, as would-be thieves in an SUV failing to break Robert Schwien’s car window in Oak Lawn.

“By the time I went to the door, they were gone,” Schwien said.

But he checked the security camera at Oakdale Drive and Washington only to find more. In the minutes before the banging, a person takes a picture of something in the front windshield you. They walk back to the door then to the dashboard again – another flash.

“Right when I saw that, I knew what was going on. With my daughter’s car, they used a VIN number to cut a key for it,” Schwien said.

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VIN – standing for Vehicle Identification Number.

“That’s basically the birth certificate or DNA of a car.”

Locksmith Thomas Thill said that info gives thieves the type of car parts to steal. Or, when it comes to copying a key fob, the year of the vehicle. His staff uses it for their work.

“If they’re (staff) going to do a Dodge, if they’ve got the right part and machine, they can usually do the marriage ceremony in under five minutes.”

CBS 2 has reported before about fob replica crimes involving many car types. Matt Nalett runs Chicago Stolen Car Directory on Facebook and said it can happen to cars repeatedly.

“Because those people might be back and try to steal the car again. That’s happened before, too,” Nalett said.

But just this month, Dodge announced new safety add-ons like “key-programming lockdown” which prevents thieves from programming key fobs after breaking into a vehicle.

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Luckily, Schwien only had scratches to his window. And when it comes to protection of all types, experts said an easy addition is to get secondary alarm system to ward off thieves.