The deputy was identified as Darren Goforth, 47. He was a 10-year veteran of the Harris County Sheriff's Office, assigned to the west district patrol. He leaves behind a wife and two children.
Deputy Goforth was pumping gas at the service station on when someone walked up and shot him repeatedly.
"A male suspect came up from behind the deputy and shot the deputy multiple times. The deputy then fell to ground. The suspect then continued over to him and shot the deputy again multiple times as he laid on the ground," Gilliland said.
Deputy Goforth died at the scene.
Gilliland says they think this may have been a random vicious act.
"This is a very tough moment right now for the Harris County Sheriff's Office. I can ask you if you give us your prayers and your thoughts," Gilliland said. "It's tough enough being a deputy and being in law enforcement in this country right now, but for people, the way that they are right now, I have no words for what this type of person did, the callousness is much."
Officers described the shooting suspect only as a dark-complexioned man who's about 5 feet 11 inches tall. He had short hair, possibly a fade cut. He was wearing a white T-shirt and red shorts at the time of the shooting and fled the scene in a dark red Ford Ranger.
Tonight we lost one of our brothers. This is an extremely difficult time right now for the Harris County Sheriff's Office. #ThinBlueLine— HCSOTexas (@HCSOTexas) August 29, 2015
"We are actively searching for this suspect as of right now. I can tell you that with diligence and justice, this suspect will be caught and he will be brought to justice," Gilliland said.
Mckenzie Stalter heard the shots ring out.
"We were driving on West Road and we heard the shots, and when I turned and looked, the lady was screaming over top of him. So we busted a U-turn into the parking lot and that's when we saw what had happened," Stalter said.
Stalter says she saw a woman sobbing over Deputy Goforth's body.
"She was laying on top him. She was saying that was her best friend and that he had two kids," she said.
Stalter says the suspect was gone by the time she had pulled into the parking lot and called 911.
This shooting marks the first time a Texas law enforcement officer was fatally shot this year. This is the first officer slaying in the Houston-area since 2012.