A one-time chief of staff to former Oklahoma Rep. Ernest Istook has been charged with conspiracy to defraud the House as part of the Jack Abramoff scandal.

John Albaugh is accused of accepting meals, sports and concert tickets, and other perks from lobbyists in exchange for official favors, according to charges outlined in a criminal information filed in federal court on Friday.

Such documents are normally entered as part of a plea deal. Albaugh was expected to appear at a court hearing Monday afternoon.

Albaugh served eight years as top aide for Istook, who left Congress to run for governor of Oklahoma in 2006. Istook lost and is now a fellow at the Heritage Foundation, a conservative think tank in Washington.

Istook, who has not been charged with any wrongdoing, accepted tens of thousands of dollars in campaign contributions from Abramoff and his associates. Referred to as "Representative 4" in court documents, he also used the lobbyist's skybox tickets for concerts. He later donated the campaign money to charity and paid for the seats.

Abramoff has pleaded guilty to bribing lawmakers to support policies that helped his clients, including Indian tribes. Istook was among 33 lawmakers who accepted Abramoff-related money and wrote letters urging the Bush administration to reject a casino proposal that Abramoff's clients opposed. He has said the letter was unrelated to the campaign contributions.

"I signed the letter as part of my long-standing opposition to the spread of gambling, and for no other reason," Istook said in 2005.

Throughout the court documents Albaugh is depicted in close contact with "Lobbyist C," asking him for sports tickets, fundraisers for his boss and other favors. In return Lobbyist C, identified as a co-conspirator, gets help with money for transportation projects for his clients.

Albaugh was in a position to help as chief of staff to Istook, who chaired the House Appropriations subcommittee on transportation, treasury and independent agencies.

Lobbyist C is not identified by name, but details in the documents make clear that it is Kevin Ring, a one-time aide to Rep. John Doolittle, R-Calif., who later went to work for Abramoff.

Messages were left seeking comment at Albaugh's office Friday. Istook and Ring did not immediately return a call on Monday seeking comment.

Ring and Doolittle both are under investigation in the Abramoff probe. Doolittle is retiring from Congress at the end of this year, partly because of the investigation.

Court documents describe a series of e-mails in 2002 in which Ring told Albaugh, "You are going to eat free off of our clients."

The documents also allege that Istook called Abramoff in 2003 to thank him in advance for use of one of Abramoff's suites at FedEx Field in Landover, Md., for a fundraising event. During the call, the government alleges, Istook asked Abramoff which projects his clients wanted in the upcoming transportation bill.

The documents refer to an e-mail Abramoff sent to his lobby colleagues saying Istook "had basically asked what we want in the transportation bill," and instructing the lobbyists to "make sure we load up our entire Christmas list."

The documents allege that four of Lobbyist C's clients later received at least $1 million each in the transportation bill.

The clients aren't named, but Ring represented a number of municipalities, including around Doolittle's Northern California district, that were seeking money for transportation projects.

Abramoff is serving prison time for a fraudulent Florida casino deal and is still awaiting sentencing in his scheme to bribe public officials in Washington. As part of his plea deal, he agreed to become a witness against the Washington power-brokers he once treated to lavish meals, golf vacations and money.

Though Istook's congressional campaign had to repay one of Abramoff's companies for the use of skyboxes for an "American Idol" concert and a Washington Redskins football game, he has repeatedly denied any ties to the disgraced lobbyist.

"I barely knew the man," he said in 2006. "I never worked with him on any issue or any project and I'm appalled at what he has done."