CHICAGO -- Former Illinois Gov. Rod Blagojevich once said his closest confidant in the world besides his wife was former top aide Alonzo "Lon" Monk, the faithful friend always by Blagojevich's side as he climbed the political ladder.

Monk was Blagojevich's counsel in Congress, his campaign manager and chief of staff in the governor's office. He went on to become a high-powered lobbyist in Springfield, using his close ties to the governor as a launching pad.

When Blagojevich was indicted in April on charges that included trying to sell President Barack Obama's former Senate seat, Monk was there as well - a co-defendant in the alleged corruption prosecutors say swirled around Illinois government.

But Monk's role dramatically changed Tuesday when he went from close ally to federal witness, pleading guilty to wire fraud and agreeing to tell prosecutors what he knows about the underside of the Blagojevich administration.

Monk's testimony at Blagojevich's trial, due to get under way June 3, could prove devastating.

"Lon Monk was in the governor's office day after day as jobs and contracts and appointments were traded for campaign contributions in the boldest and crudest way," said Andy Shaw, director of the Better Government Association.

In a 31-page signed plea agreement, Monk, 51, said he had witnessed efforts to shake down roadbuilders, a hospital executive and a racetrack owner for hundreds of thousands of dollars in campaign contributions for the governor.

Monk said that even before Blagojevich was elected there was talk of using the powers of the governor's office to raise a cash horde that would eventually be divided up among an inner circle of key advisers.

Blagojevich has pleaded not guilty to all such charges, and one of his attorneys, Sheldon Sorosky, scoffed at any notion a cash horde existed. He said Blagojevich is in New York, taping Donald Trump's "Celebrity Apprentice."

Two-year sentence for Monk

Under the plea agreement, Monk will get a lenient 24-month sentence as his reward if prosecutors are satisfied with the help he provides. Federal guidelines call for a 37 to 46 month sentence for the single count of wire fraud.

Cooperation could include testifying against Blagojevich, and that could be painful because the two go back a long way.

Monk was Blagojevich's law school roommate and jogging partner at Pepperdine University in Malibu, Calif. He was a groomsman at Blagojevich's wedding. Speaking about the 2002 campaign, Monk made it clear he was close to the governor.

"Managing the guy running for governor is not unlike managing a professional athlete," Monk said. "You wake him up in the morning and put him to bed at night and make sure all the little things are taken care of during the day so he can be the best governor he can be."

Monk is not Blagojevich's only supporter to offer cooperation. His successor as chief of staff, John Harris, has made a similar deal.

Prosecutors have not announced that convicted influence peddler Tony Rezko, another member of Blagojevich's inner circle, is cooperating. But his sentencing has been deferred indefinitely - a sign that he may be spilling secrets.

Another key Blagojevich adviser, contractor Christopher G. Kelly, was found dead in what police say was a suicide, just days before he was to report to prison to serve at least eight years for fraud. Prosecutors had been hoping Kelly, who was facing even more charges as a Blagojevich co-defendant, would change his mind and agree to cooperate in return for a reduced sentence.

Among other things, Monk said in his signed plea agreement that there was discussion among Blagojevich's advisers of allowing the governor's wife, Patti, to market a giant Rezko real estate project involving 62 undeveloped acres a few blocks south of the heart of downtown Chicago.

Rezko had planned to put a shopping center and homes on the site, but it was announced shortly before his trial that he transferred his share to a London-based billionaire.

Monk said he met with Blagojevich, Rezko and Kelly periodically in the early days of the administration to discuss ways of using state power to make money. But he said the meetings stopped abruptly in 2004 after they learned that FBI agents were questioning big-money campaign contributor Stuart Levine - who later became the government's star witness at Rezko's influence peddling trial.

Monk said Rezko gave him about $10,000 in cash seven to nine times and made it clear he did not have to repay.

He said he learned from Kelly and Rezko that Rezko would get a $500,000 share of a consulting fee paid in connection with the refinancing of $10 billion in state pension bond.

Bob Kjellander, a Springfield lobbyist and a former treasurer of the Republican National Committee, received an $809,000 commission from the now defunct Bear Stearns investment firm after it became prime underwriter for the pension bonds. He issued a statement Tuesday saying he has met Monk and knows Rezko but never took part in a scheme to provide them with money and hasn't committed any crime.