SEATTLE - KING 5 News has learned that thieves are trying to cash in on the high cost of a gallon of gas.

Police get a lot of calls for what they call gas drive-off's -- someone filling up a tank of gas and taking off without paying. But one sheriff's official says what happened recently was "the mother of all gas drive off's."

Surveillance cameras recorded men pumping nearly 200 gallons of diesel and premium fuel into blue barrels at a West Seattle Shell station located on 2805 SW Roxbury Street. The station was closed, but the pumps were running for overnight credit card customers.

The thieves stole 700 gallons, up to $3,000 worth of fuel, before station owner John Henry knew it was missing.

"I have been in this business for 15-years," he said. "This is first time."

It's believed the criminals who struck in West Seattle also hit least one other gas station in Sea-Tac last week. They used a gift card with 68 cents on it to turn the pump on and then somehow broke into the pump to keep the fuel flowing.

Investigators are analyzing the video and asking for the public's help in identifying the people or vehicles in it.

The sheriff's office says this is the first time it's seen this type of bulk fuel robbery.

"Obviously they're selling it someplace and that's what's most interesting to us -- who's buying this gas?" said Sgt. John Urquhart, of the King County Sheriff's Office.

John Henry earns only pennies per gallon on the fuel sold at his shop, and customers are angry that someone would steal from the hardworking owner.

"I feel sorry for him; he's great in the community," said David Dean Smith. "He's a great guy."

The thieves hit the Shell Station early Tuesday and Wednesday morning. Anyone who saw anything is asked to call the King County Sheriff's Department.

Investigators also warn that the thieves are creating a serious hazard by carrying so much fuel in the back of a pick-up truck.