A reward has been increased for information about a man's death outside a southwest Harris County gas station.

Raul Amaro, 60, was killed during a robbery at a Conoco station in the 13100 block of Bissonnet about 7:30 p.m. on Nov. 28.

Harris County sheriff's deputies said Amaro was standing outside the gas station with friends when two armed men demanded cash.

Amaro fought back and was shot during a struggle, investigators said. He died at a hospital.

Amaro's family said moving forward has been tough, especially since his killers are still on the streets.

"A wonderful father, grandfather," said Raquel Ramirez, Amaro's niece. "He was a protective citizen. A senseless crime was committed. This crime cannot go unpunished."

Detectives said the gunmen are black, 20 to 30 years old with slender builds and short hair. One of the men was last seen wearing a long-sleeved white shirt under a red T-shirt and the other was wearing a black sweatshirt.

"The suspects fled the location on foot," Deputy Jason Brown said. "We believe the suspects are from that part of town."

An $11,000 reward has been offered for information that leads to felony charges being filed in the case. Anyone with information is asked to call Crime Stoppers at 713-222-TIPS.