A federal judge sentenced a onetime media aide to former House majority leader Tom DeLay to 20 months in prison Thursday, crediting him with serving as a key government witness in the unraveling of the corruption scandal surrounding the congressman and lobbyist Jack Abramoff.

Michael P.S. Scanlon, 40, a communications director for DeLay (R-Tex.) who became a top partner with Abramoff, also was ordered to repay $20.2 million to five Native American tribes whom he defrauded in a kickback scheme with Abramoff's lobbying firm.

"I am so very sorry and so very remorseful," Scanlon told U.S. District Judge Ellen S. Huvelle in the District. "I hope that my cooperation and the things I've done to make amends show how remorseful and sorry I am."

Huvelle acknowledged Scanlon's help to prosecutors. "Your cooperation, I think it's fair to say, has been extraordinary and extensive," she said. However, the judge added, Scanlon took part in a years-long scandal that undermined public confidence and exposed widespread corruption.

"The money that you got fueled the corrupt scheme," Huvelle said.

Scanlon, a former Rehoboth Beach lifeguard who became a wealthy public relations consultant and real estate developer after working with DeLay, was the last leading figure of the Abramoff scandal to face sentencing.

In November 2005, Scanlon became the first person to strike a plea deal and cooperate with prosecutors in the public integrity and fraud sections of the Justice Department's criminal division.

Eventually, the investigation exposed how Abramoff worked at the center of a lucrative network of lobbyists from 2000 to 2005, showering lawmakers, congressional aides and executive branch officials with lavish gifts, golf trips, luxury meals and tickets in exchange for millions of dollars in taxpayer-funded projects, legislative favors and other benefits.

The Abramoff scandal prompted DeLay to step down in 2005 and helped Democrats win control of Congress the next year, decrying Washington's "culture of corruption."

In addition to Abramoff, who recently completed a four-year prison sentence, former congressman Robert W. Ney (R-Ohio), was sentenced to 21/2 years in prison, and former deputy interior secretary J. Steven Griles received 10 months.

Overall, the case led to 21 convictions - a 100 percent success rate of those charged - and prosecutors credited Scanlon's early, detailed cooperation.

"Without Mr. Scanlon's cooperation, the investigation would have taken much longer," prosecutor Nathaniel B. Edmonds said in court. "It may not have been able to reach Mr. Abramoff or others."

Steven Brand, assistant district attorney for Travis County, Tex., wrote to Huvelle that Scanlon's help was "a breath of fresh air" as his office prepared to try DeLay for illegally plotting to steer corporate contributions to Texas legislative candidates. The former lawmaker is free while appealing his three-year prison term.

Scanlon faced up to five years in prison for admitting to conspiracy to commit bribery, fraud and honest-services fraud by bribing a congressman and other public officials.

Prosecutors said Scanlon's firm netted $39.5 million from casino-rich Indian tribes and kicked back $20 million to Abramoff, who referred them to Scanlon. As part of his schemes, Abramoff manipulated tribal elections and worked simultaneously with anti-gambling forces to threaten tribes and gain more business.

The court ordered Scanlon to pay $20.2 million in restitution to the Coushatta, Mississippi Choctaw, Saginaw Chippewa, Puebla of Sandia and Tigua del Sur Puebla. Abramoff shares liability, but is broke.

"I don't know where I'm going or what I'm doing" next, Scanlon told Huvelle in response to a question. After his release, he said, "I want to be working in my field, developing properties, helping my community."

David Sickey, vice chairman of the Coushatta Tribe, called the 20-month sentence "light," considering the scope of Scanlon's crime.

"It's disappointing, to be honest," he said. The tribe paid about $32 million to Abramoff and his partners and was eligible for about $11 million in restitution.