“No Sandlin property, no bill,” the Congressman allegedly said in 2005, meaning he would block the bill if Mr. Sandlin were not included in the profitable deal. The deal netted Mr. Sandlin some $4.5 million, prosecutors say.

Mr. Sandlin, who was also indicted on the extortion, fraud, money-laundering and conspiracy charges, was a heavy contributor to Mr. Renzi’s first campaign in Arizona’s First Congressional District, in 2002. The indictment said that Mr. Renzi and Mr. Sandlin concealed at least $733,000 that the Congressman took for helping the lucrative land deal go through.

“Congressman Renzi misused his public office by forcing a land sale that would financially benefit himself and a business associate, and in so doing, he betrayed the trust of the citizens of Arizona,” said the United States attorney for Arizona, Diane J. Humetewa.A lawyer for Mr. Renzi, Kelly Kramer, disputed that description of events, telling The Associated Press that the Congressman had done nothing wrong. “We will fight these charges until he is vindicated and his family name is restored,” the lawyer said.

Mr. Renzi and another defendant, Andrew Beardall, 36, of Rockville, Md., are also accused of embezzling more than $400,000 in premiums from an account in an Arizona insurance business owned by the Renzi family to help finance Mr. Renzi’s first Congressional campaign.

“Essentially, the indictment alleges two courses of criminal activity and conduct,” Ms. Humetewa said at a news conference. "First, that Congressman Rick Renzi embezzled funds from his own insurance company’s trust accounts, and he used those funds to finance his first congressional campaign in 2001 and in 2002. And acting together, he and Andrew Beardall conspired to get out from under billing statement and state regulatory acts, and in so doing, they made false statements and misrepresentations to regulatory agencies.”