It happened in the 12100 block of Almeda on Sept. 11.
The victim told officers he was leaving the store when he was suddenly attacked from behind.
One suspect pushed the victim to the ground, hit his head and went through his pockets, while two other men searched the victim's vehicle.
One of the men managed to take the victim's concealed handgun, but once they realized the man didn't have any money, they ran back to their vehicles and fled.
They drove off in a white van and a black Dodge Challenger, according to police. The white van was located and recovered by officers shortly after. It had been reported stolen.
One suspect is described as a Black male around 23 to 28 years of age. He stands around 5'6 to 6'1 feet tall and weighs about 170 pounds. He was last seen wearing Nike sandals, a gray coat and blue shorts.
The second suspect is described as a Black male around 20 to 26 years of age. He stands around 5'5 to 5'10 feet tall and weighs about 140 pounds. He was last seen wearing a white shirt with black shorts and black sandals.
The third suspect is described as a Black male around 25 to 30 years old. He stands around 5'6 to 6'0 feet tall and weighs about 180 pounds. He was last seen wearing a light blue shirt, blue shorts and black sandals.
Anyone with information on the suspects is urged to contact Crime Stoppers by calling 713-222-TIPS (8477) or you can submit your tip online.