By Jon Jordan, NEWS 9

OKLAHOMA CITY -- Many people start their cars early in the morning to warm them up before their commute. However, leaving a car unattended not only makes it an easy target for thieves but it is also illegal.

One Oklahoma City family learned an expensive lesson. For the Rios family, Thursday morning was anything but fun.

"You never know what can happen in a second," said Carina Rios, whose car was stolen after she left it running unattended.

The Rios now have to repair the tire to their truck after police discovered their vehicle in a neighborhood after it was stolen. The vehicle was taken from their own driveway after they left it running.

"It's scary because I have kids at home too, and I normally turn my car on in the morning to drop them off," Rios said.

The Rios' did what many others do when the temperatures drop; they leave their cars running to keep it warm, and for some stepping away from their vehicle spells trouble.

"It's takes a thief just a second to jump into a car already warming up. It's running, its unlocked and all they've got to do is put it in gear and drive off," said Oklahoma City Police MSgt. Gary Knight.

But what many people don't know is leaving their car unattended is against the law.

According state statue Title 47, 11-1101, "The person driving or in charge of a motor vehicle shall not permit it to stand unattended without first stopping the engine, and effectively setting the brake..."

It's unclear how much a ticket for leaving a car running unattended would cost because the law is rarely enforced.

Police say someone stole four cars in the Rios' neighborhood on Wednesday, all of them where unattended running vehicles.