Authorities on Thursday charged a man in what they say was a plot to kidnap U.S. talk show host David Letterman's (search) toddler son and nanny from the star's Montana home.

Kelly A. Frank, 43, was being held on a felony charge of solicitation, among others.

Montana Department of Corrections (search) spokeswoman Sally Hilander said the plot was uncovered when someone whom Frank had approached about the plan informed local police.

Steven Rubenstein, a spokesman for Letterman's production company World Wide Pants (search), said he could not immediately comment or say whether Letterman or his family was in Montana at the time of Frank's arrest.

The comedian who hosts CBS' "Late Show" taped three programs earlier this week, but is not on the air Thursday and Friday because of the network's coverage of the men's college basketball tournament.

Mike Ferriter of the state Department of Corrections said Frank had been working as a painter at Letterman's ranch west of Choteau in north-central Montana and apparently confided in an acquaintance earlier this month of his plan to kidnap Letterman's son and nanny and hold them for $5 million ransom.

According to the affidavit filed by Teton County Attorney Joe Coble, Frank had talked in detail with the acquaintance about his kidnapping plan.

He told the man that he knew Letterman and his family would be visiting their Montana home soon, and that Frank had a key to the house, knew where the baby slept and intended to kidnap the nanny "so that she could take care of the child."

The acquaintance contacted authorities on Sunday, according to the affidavit. Sheriff George Anderson told the weekly Choteau Acantha newspaper that Frank was arrested the following morning at another area ranch where he was working. Anderson did not return phone calls to The Associated Press seeking comment.

In addition to the solicitation charge, Frank also is charged with felony theft for allegedly overcharging Letterman for painting, and obstruction for lying to investigators who first contacted him about the alleged plot.

Letterman's girlfriend, Regina Lasko, gave birth to their son on Nov. 3, 2003. Letterman said that the boy, his first child, was named after his late father, Harry Joseph Letterman.

He bought the 2,700-acre Montana spread in 1999.

Letterman's ranch is along the edge of the rugged Rocky Mountain Front, an area known for its pristine wildlife habitats and home to wolves, eagles and grizzly bears. In September 2003, a black bear broke into Letterman's home twice, then was captured and relocated after returning a third time.

For years, Letterman was famously targeted by a stalker, who called herself "Mrs. David Letterman" and broke into his Connecticut house at least seven times.

Margaret Ray eventually pleaded guilty to breaking and entering. Diagnosed with schizophrenia, she served 10 months in prison and 14 months in a mental institution. In 1998, she committed suicide at age 46 by kneeling in front of a train.