SAN ANTONIO -- A 37-year-old man shot a 21-year-old man who police said was planning to rob him, police said.

Maymi Russell posted a listing to sell a camera on Craigslist, but he decided to do some research on Facebook on the potential buyer, Sammy Villa, before meeting him, said Sgt. Chris Benavides, a San Antonio Police Department spokesman.

When Russell arrived at behind an IHOP Monday afternoon to make the transaction, he saw a man who motioned Russell to finish the transaction, Benavides said.

Russell noticed something was wrong when two other men approached him. Moments later, they demanded the camera from him, Benavides said.

But Russell, who is licensed to carry a weapon, pulled out a gun and shot Villa, Benavides said. The two other men, John McFarland and Cameron McFarland, took off but were later arrested. The three were charged with aggravated robbery and were being held in the Bexar County Jail in lieu of $75,000 bond.

Benavides said that Russell saved his life by being alert and aware of his surroundings but he still should have met the men in a spot where there were people.

"Meet where there's a lot of people around, Benavides said. "You want witnesses should you be the target of a robbery."

Villa was transported to Wilford Hall Medical Center with non-life-threatening injuries.