Sandy Springs police are investigating a bizarre theft from a local restaurant involving gallons of used kitchen grease.

Channel 2's Mike Petchenik talked to the owner of Makara Mediterranean on Roswell Road who said someone stole their used grease and sold it to a recycling company.

"She was doing something with a pipe, pulling the oil," owner Ertan Makara told Petchenik after finding a woman behind his restaurant last week.

"I said, 'Who are you? Which company are you with?'"

Makara said the woman pretended to be a contractor working with a grease recycling company, so he asked for proof.

Police said the woman was after the used oil from the restaurant, which is becoming liquid gold on the black market.

Sandy Springs police Capt. Steve Rose told Petchenik used kitchen grease fetches good money from recyclers, who turn it into alternative fuel.

When oil prices spike, so do these kinds of thefts.

"Now there seems to be a bigger demand," Rose said.

Petchenik found a YouTube video of someone stealing grease from a California restaurant earlier this year.

"Any kind of market that's in demand, they'll steal it. In this case, it's in demand as a biodiesel fuel. You would expect to see more, so that trend continues," Rose said.

Makara told Petchenik he recently received a letter from his recycling company warning of similar thefts across metro Atlanta, so when the suspicious woman showed up, Makara said his intuition kicked in.

"I'm gonna go to Lowe's and buy a lock to secure it," Makara said.

Makara thinks the thieves made off with about $100 worth of grease.

Police don't have any solid leads at this point but told Petchenik they suspect the thieves will strike again as long as oil prices stay high.