TULSA, Oklahoma - Police officers said thieves stole several vehicles Wednesday morning after the owners left them warming up.

Police call leaving an unattended car running puffing and it's illegal in Tulsa.

News On 6 crime reporter Lori Fullbright first aired a "puffer" story in December 2013.  

Police said a puffer is a person who starts a vehicle and then goes back inside until the vehicle warms up. If a thief comes by and sees a puff coming from the vehicle's tailpipe He instantly knows it's an easy target. 

On Wednesday, almost all the thefts happened at Tulsa area convenience stores.

Lori reports thieves steal about 2,800 vehicles in Tulsa every year and detectives say a third of all those happen while the car is running and the owner is not around.