Deputy constable killed at Texas courthouse, gunman sought Clint Greenwood, a 30-year veteran, was shot around 7 a.m.

 -- A manhunt is underway in Harris County, Texas, for the gunman who shot and killed a veteran deputy constable at a courthouse this morning, officials said.

Harris County Precinct 3 Asst. Chief Deputy Clint Greenwood, a 30-year veteran, was shot around 7 a.m. local time as he was arriving for work, Baytown Police Department Lt. Steve Dorris said at a news conference.

According to ABC station KTRK in Houston, investigators said Greenwood "was shot in the neck and radioed for help, reportedly saying, 'I'm bleeding out.'" Dorris told ABC News he could not confirm that report.

Responding officers rendered aid but Greenwood later died at the hospital, officials said.

It's unclear if Greenwood was targeted and there is no known motive, they added.

Dorris called it "very early on in the investigation."

Harris County Sheriff Ed Gonzalez said, “Thousands of men and women faithfully wear the badge of a Texas peace officer day in and day out in Houston and Harris County. ... They answer a high call to service for their fellow man. That was the call that Assistant Chief Clint Greenwood answered over decades of service. His bravery and sacrifice will not be forgotten and will not go unanswered.”

Greenwood began his career in 1988 with the Harris County District Attorney’s Office and later worked at the Harris County Precinct 4 Constable’s Office and the Harris County Sheriff’s Office. In January, he was selected to serve as Assistant Chief in the Harris County Precinct 3 Constable’s Office, officials said.

The Office of the Governor’s Criminal Justice Division is offering a reward of up to $15,000 for information leading to the arrest of the suspect or suspects. Baytown Crime Stoppers has also offered a reward of $35,000.

Tips can be submitted at the Baytown Crime Stoppers hotline at 281-422-TIPS or the Texas Crime Stoppers hotline at 1-800-252-TIPS.