Updated: 10/21/10 5:37 p.m.

DENVER (CBS) — A 72-year-old Gold Coast businessman has been arrested at Denver International Airport and is accused of trying to hire a hitman to commit a murder.

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The FBI tells Newsradio 780’s Steve Miller that 72-year-old Brooks Kellogg, whose address is listed at 111 East Chestnut, flew to Denver this week to hire a hitman to have a man shot to death. Kellogg was taken into custody on Tuesday after allegedly paying $2,000 in cash to an undercover FBI agent posing as a hit man, CBS station KCNC in Denver reports.

Was it for revenge? That’s something investigators want to know. Their primary source for information, according to court documents, is a woman who claims to be Kellogg’s mistress.

The meeting took place after an exchange of e-mails in which the FBI claims Kellogg revealed he wanted to have a man killed who had won $2.5 million in a lawsuit against him. The lawsuit involved Kellogg’s Steamboat Springs real estate development business called Chadwick Real Estate Group, based in Colorado.

Kellogg is a developer, who also owns and manages an office building in Libertyville, according to the feds. He also owns a home in Chicago, has an Illinois driver’s license and has a vehicle with Illinois plates.

According to court records, the so-called mistress said she went to authorities when she heard Kellogg wanted to hurt Stephen Bunyard, the man who won the lawsuit.

She turned over a series of instant messages and texts, in which she then posed as a hitman.

In one message, Kellogg is accused of writing: “Well, our thought was to give him a warning, but if that’s not safe for you to do then the bullet is fine.”

Kellogg was taken into custody after meeting the undercover FBI agent at Denver’s airport on Tuesday, with the $2,000 to kill Bunyard.

The court documents state Kellogg was asked by the FBI agent: “You want him killed?”

The reply was, “Yes.”

Then the agent asked Kellogg, “Do you have any other jobs for me?” and Kellogg responded, “Yeah, I’ve got some other things in mind.”

Prosecutors admit the woman claiming to be his mistress has a lengthy criminal history, and that she has given them misleading and inaccurate information in some respects. But they believe they have enough evidence to prove the important allegations.

Neighbors who know Kellogg from the Gold Coast condo he shares with his wife were shocked by the charges. Karen Patton described Kellogg as well-connected and well-traveled.

 “That is amazing,” neighbor Vincent Scott said. “I mean, I don’t see that in his capacity in any way.”

CBS 2’s Dorothy Tucker contributed to this report.

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