With help from a member of the Avalon Police Department, we are here to reveal the car thieves' hack to know when expensive vehicles are unlocked as soon as they drive by and see them without checking the doors or looking suspicious.

This tip actually came from a member of Facebook's All Things Avalon page. The man said an Avalon Police officer recently rang his doorbell to tell the man that his car doors were unlocked.

The cop knew this immediately as he drove by on patrol and decided to let the vehicle's owner know to lock up before the Range Rover ended up being stolen.

The officer knew this the same way a car thief would know it and now you will know, too.

Most newer, high-end vehicles -- the kind that car thieves are looking for these days-- come with side-view mirrors that automatically fold inward when the doors are locked.

The officer drove by and saw a Range Rover parked with its side mirrors unfolded and instantly knew that car was unlocked.

The Avalon Police officer also correctly told the man that there has been a rash of thefts of high-end vehicles from South jersey shore towns lately and he would be smart to keep his doors locked and his side mirrors folded in.

Now we know what the car thieves know. Lock up.

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