DENVER (AP) — The head of the Colorado Department of Corrections was shot and killed when he answered the front door of his home, and police were searching for the gunman Wednesday.

Tom Clements was shot around 8:30 p.m. Tuesday at his home in Monument, north of Colorado Springs, said Lt. Jeff Kramer, of the El Paso County Sheriff's Office.

A family member called 911 to report the shooting and officers found 58-year-old Clements dead in his home, he said. Search dogs have been called in to comb through a wooded area around Clements' home, and authorities were going house to house trying to find out what neighbors heard and saw.

Gov. John Hickenlooper appointed Clements to the post in 2011 after he served for more than three decades in the Missouri Department of Corrections. He replaced Ari Zavaras, a former Denver police chief who led the department under two governors.

The department operates 20 adult prisons and a juvenile detainment system.

In a statement released early Wednesday and sent to department employees, Hickenlooper said he was in disbelief over the killing.

"As your executive director, he helped change and improve (the department) in two years more than most people could do in eight years. He was unfailingly kind and thoughtful, and sought the 'good' in any situation. I am so sad. I have never worked with a better person than Tom, and I can't imagine our team without him," Hickenlooper said.

The governor said he's awaiting further details.

Clements is survived by his wife, Lisa, their two daughters and their family.

Hickenlooper asked the public to respect their privacy.