Two inmates, including a man who was once accused of plotting to kidnap David Letterman's son, escaped from the Montana State Prison while working on the prison's ranch Friday.

Kelly A. Frank, 45, and William J. Willcutt, 22, apparently left in one of the prison's work trucks, officials said. Authorities were still searching for them late Friday.

Frank was arrested in 2005 on allegations he was plotting to kidnap Letterman's young son and nanny from his Montana home. However, kidnapping-related charges were eventually dropped, and Frank was sentenced to 10 years for theft for overcharging Letterman for painting work.

Willcutt was in prison on theft and burglary charges, said Bob Anez, communications director for the Department of Corrections.

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Both men were assigned to a crew that moves irrigation pipe on the prison's ranch, just west of the prison.

A ranch supervisor first noticed Willcutt and the half-ton spray truck were missing at about 4:20 p.m. Friday, a prison news release said.

The institution's shift commanders were notified immediately, and the prison was placed on lockdown, the release said. A subsequent inmate count showed Frank was also gone. The missing truck had been assigned to Frank, the release said.

Officers began an immediate search of the prison and outside areas, and area law enforcement agencies and the Montana Highway Patrol were notified, the release said.

The 1965 truck was found off prison property at about 5:30 p.m. Anez declined to say where the truck was found, but said the search for Willcutt and Frank was focused in an area south of Deer Lodge.

Frank was arrested in March 2005 on allegations he had devised a plan to kidnap Letterman's son, lied to investigators, and overcharged Letterman for paint work.

Prosecutors later agreed to drop a solicitation to kidnap charge against him, in exchange for guilty pleas on three other charges: felony theft, misdemeanor obstruction and an unrelated felony charge of possessing illegally killed wildlife. He was sentenced to 10 years in September 2005.

Frank was then given another 10-year sentence in an unrelated case. A district judge revoked his suspended sentence for a 1998 conviction for stalking and intimidating a woman. Frank was on supervised release on that charge when he was arrested in March 2005.

That 10-year sentence was to run concurrently with the 10-year sentence he received for felony theft for overcharging Letterman.

Telephone and e-mail messages Friday to Kim Krizzo-Emmet, Letterman's publicist at CBS, were not immediately returned.

Meanwhile, Willcutt received a 10-year sentence, with five years suspended, on theft and burglary charges out of Lewis and Clark County, Anez said.

Anez said Willcutt has been living in a prison work dorm, while Frank has been housed inside the prison.

Willcutt is 6-foot-2 and weighs 210 pounds. He is a white man with a fair complexion and a stocky build. He has blue eyes and blond hair, the release said.

Frank is 6-foot-2 and weighs 185 pounds. He is white and has a medium complexion, medium build, brown hair and blue eyes, the release said.

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