Tom Clements, director of the Colorado Department of Corrections, was shot and killed Tuesday night when he answered the door of his home in Monument, Colo. / KUSA

by Doug Stanglin, USA TODAY

by Doug Stanglin, USA TODAY

Colorado's top state prison official is dead after being shot at the door of his home, setting off a hunt for the shooter and raising questions about whether the attack had anything to do with his job.

Tom Clements, executive director of the Colorado Department of Corrections, was shot and killed Tuesday night as he answered the door at his home in a rural, wooded area north of Colorado Springs, authorities said.

El Paso County Sheriff's Lt. Jeff Kramer said Clements was shot in the chest around 8:30 p.m. by an unknown assailant who range the doorbell of his home in an upscale section of Monument, Colo.

As executive director of the Department of Corrections, the 58-year-old Clements was responsible for all state and private prisons and parole operations.

Kramer said authorities are "sensitive" to the fact that Clements' job overseeing the prison system might have made him a target for an attack, but remain "open-minded" to other theories to explain the killing. He said robbery did not appear to be a motive.

State officials, however, took the precaution of increasing security for top Colorado officials and at the governor's mansion.

While Clements generally kept a low profile, his killing comes a week after he denied a request by a Saudi national to serve out the remainder of a Colorado prison sentence in Saudi Arabia.

Homaidan al-Turki, a well-known member of Denver's Muslim community, was convicted in state court in 2006 of unlawful sexual contact by use of force, theft and extortion and sentenced to 28 years to life in prison. Prosecutors said he kept a housekeeper a virtual slave for four years and sexually assaulted her. A judge reduced the sentence to eight years to life. Clements cited al-Turki's refusal to undergo sex offender treatment.

Al-Turki insisted the case was politically motivated. He owned a company that some years ago sold CDs of sermons recorded by Anwar al-Awlaki, killed in a drone strike in Yemen in 2011.

Al-Turki's conviction angered Saudi officials and prompted the U.S. State Department to send Colorado Attorney General John Suthers to Saudi Arabia to meet with King Abdullah, Crown Prince Sultan and al-Turki's family.

After Clements' shooting, someone with the State Department called the Colorado Corrections Department. Prisons spokeswoman Alison Morgan said she had no details on the call other than to say it wasn't connected to the shooting investigation and may have been a simple courtesy.

"They called us because we have a cooperative international program with them," she said.

Attorney Henry Solano, one of al-Turki's attorneys, told USA Today he has not been contacted by investigators and has not spoken lately with his client. He declined further comment.

Kramer said a family member who was home at the time of the attack called 911, but he declined to indicate whether that person also witnessed the shooting.

The Denver Post reported that arriving officers found Clements and his wife inside the home on a set of stairs. Medical crews started performing CPR, but he died at the home, the newspaper reported.

Search dogs were called in to comb through a wooded area around Clements' home, which is tucked out of sight at the end of a long, winding driveway. Authorities went house to house trying to find out what neighbors heard.

Kramer said later that authorities are looking for a "boxy," two-door car spotted by a neighbor outside Clements' home around the time of the shooting. He said the witness saw the car running without anyone in it, but that it was gone minutes later.

In public remarks, a grief-stricken Colorado Gov. John Hickenlooper called Clements "a great friend" who "helped define what a public servant is."

"He is going to be deeply, deeply missed," said the governor, who appointed Clements to his post two years ago.

Hickenlooper, who signed bills on Wednesday expanding background checks on gun buyers and limiting the size of ammunition magazines, said the motive behind the killing is unclear, but did call it "an act of intimidation."

"We will go forward with our work," he said. "That is the kind of thing Tom would have understood and would have supported. We expect to sign the bills, answer questions and try to continue to move this state forward."

Earlier, in a statement to the 6,000 employees of the Department of Corrections, the governor said Clements was "unfailingly kind and thoughtful, and sought the 'good' in any situation."

Before taking up his post in Colorado, Clements served for 31 years in the Missouri Department of Corrections.