Robert Lee, the owner of Paul's Grocery in Knightdale, said he lost about $500 in gas early Monday when someone broke into his gas pumps.
"I felt kind of devastated that it was happening – not surprised, but devastated," Lee said.
Security video from the general store on Poole Road showed that someone drove up at about 1 a.m. Monday and used a master key to open the pump and reset a security keypad inside, which unlocked the pump and allowed people to fill up while the store was closed.
Over the next 30 minutes, about a dozen cars filled up for free.
"Two cars pulled up. They filled up. They left. (Another) two cars pulled up. They filled up. They left," Lee said. "Free gas night at Paul's Grocery."
Lee discovered the theft when he opened the store Monday morning and found his gas pumps weren't working properly. His maintenance man quickly diagnosed the problem and said other stations in Wake County have been hit recently.
"(One station owner) went back and checked his video footage at night, and it was happening almost every night," Lee said.
People are buying the master keys online, but Gary Harris, executive director of the North Carolina Petroleum Marketers Association, said they need a bit of knowledge about the pumps to unlock the flow once they get them open.
"I think that not just every Tom, Dick and Harry would be able to steal gas using this," Harris said.
Lee said he's learned of easy ways gas station owners can thwart thieves carrying a master key, including changing the keypad code inside the pump, shutting off power to the pumps at night or changing the locks on the pumps.
Lee said he's learned his lesson. The keypad on his pump had been set to the manufacturer's default code but has been changed, he said.
A Wake County Sheriff's Office investigator is investigating the gas theft from Paul's Grocery, and Lee said he hopes the security video will help crack the case.
"There are consequences and penalties for doing wrong. I just hope the law does what they're supposed to do," he said.