Killeen police are searching for a suspect who fatally shot a security guard at a local sandwich shop early Sunday morning.

Police responded to a 911 call concerning a robbery from the Subway restaurant at 1100 Old FM 440 at 3:42 AM Sunday. There, they found a man suffering from a gunshot wound. He was transported to Baylor Scott & White Hospital in Temple in critical condition. According to a media release, the wound ultimately proved fatal.

A preliminary investigation revealed that the suspect entered the store in a ski mask. He was approached by the guard and the two had a verbal altercation, during which the suspect shot the guard. There were other people in the building at the time, but no other injuries were reported.

The suspect was described as a stocky black man standing 5'6" tall and wearing a gray sweatshirt, black shorts with red and white trim, and white athletic shoes.

Detectives ask that anyone who has information about this crime to contact Crime Stoppers at  (254) 526-TIPS, bellcountycrimestoppers.com, or via the P3 Tips mobile app.

Those submitting a tip do not have to reveal their name, and all information is anonymous and confidential.

Information leading to an arrest could net a cash reward of up to $1,000.