He was the “linchpin” who helped federal authorities reel in then-Prince George’s County Executive Jack B. Johnson in a far-reaching bribery and corruption scheme. But Patrick Q. Ricker’s extensive cooperation, which a federal prosecutor called “unprecedented,” couldn’t keep him out of prison.

U.S. District Judge Peter J. Messitte sentenced Ricker, 53, to 12 months and one day in prison Friday, ordering the prominent developer to pay $250,000 in restitution and placing him on two years of supervised release once his sentence is completed.

Ricker, of Stevensville, earlier pleaded guilty to fraud, tax evasion and making false statements to the Federal Election Commission.

His multiyear scheme included providing favors to county officials that included trips, restaurant meals and more, Messitte said.

Ricker began helping federal investigators in 2008 after they learned of his role in seeking favorable treatment for development deals during the administration of Johnson (D).

“This is corruption of some years duration, during which the county has been drained of the honest services of its officials,” Messitte said in U.S. District Court in Greenbelt. “This is not a slight transaction.”

The amount of profit Ricker stood to reap may never be fully known, because some of the development deals foundered. Prosecutors said he and others spent between $400,000 and $1 million doing favors for Johnson and others in county government.

“Prince George’s County may be on its way out of this morass, but the cleanup has really been quite an undertaking,” Messitte said.

Prosecutors have said their investigation is far from over.

Ricker is scheduled to report to prison in early January. While seeking a prison sentence of 30 to 37 months for Ricker, prosecutor James Crowell asked Messitte for leniency.

The judge agreed to the sentence proposed by Ricker’s attorney, Timothy Sullivan.

Ricker’s role spread over four years, according to court documents, interviews and statements by prosecutors. After his part in the scheme became known to authorities, he worked closely with FBI agents, meeting with county officials while wearing a wire and participating in transactions that were videotaped and recorded.

“He has done everything we asked,” Crowell told the judge.

Sullivan acknowledged that his client was a key actor in county’s “culture of corruption” for years.

“Mr. Ricker paid and he played for a long time,” Sullivan said. He read an apologetic statement from Ricker after his client wept and was unable to speak in court.

The sentencing comes two years after Johnson and his wife, former County Council member Leslie Johnson (D-Mitchellville), were arrested in dramatic fashion at their Mitchellville home on Nov. 12, 2010.

During that arrest, agents overheard Johnson on a wiretap instructing his wife to stuff $79,600 in her bra and underwear to evade FBI agents who were pounding on the door.

The Johnsons, former county housing director James Johnson and Jack Johnson’s personal physician, Mirza H. Baig, with whom he did development deals, are all in prison.

A total of 15 people have pleaded guilty in the scheme, which included numerous instances of “pay to play” in county development deals that helped enrich the Johnsons and the developers, according to court documents.

Ricker, along with co-conspirators Karl Granzow and Daniel I. Colton, regularly provided money for trips, meals, drinks, hotel rooms, employment, airline tickets, sexual services, rounds of golf and campaign contributions to state and local officials, according to court documents.

Granzow, 48, a former deputy fire chief who was a business associate and close friend of Ricker, was sentenced last month to 18 months in prison and ordered to pay a $10,000 fine and continue to repay back taxes to the Internal Revenue Service. Colton has not been sentenced.