A once-prominent Prince George’s County real estate developer was sentenced to two years in prison Tuesday, becoming the last of more than a dozen people convicted in a far-reaching public corruption scheme that took down the county’s former top executive, Jack B. Johnson.

Daniel I. Colton was one of three local businessmen who pleaded guilty to trying to influence county officials — using airline tickets, rounds of golf, hotel rooms and meals — to win favorable treatment for their development deals, including an investment near the Greenbelt Metro station.

Colton, who cooperated with the FBI for more than five years, is the final defendant to be sentenced in the long-running investigation that highlighted a “pay-to-play” culture in the county and ensnared Johnson; his wife, former County Council member Leslie Johnson; and former housing director James Johnson.

To do business in Prince George’s, Colton and other developers felt that they had to bribe public officials and county regulators, Colton’s attorney told the judge Tuesday.

“The deal in Prince George’s was that you had to pay to get on to the field,” said Colton’s lawyer, Andrew Graham. “He had a distaste for the way things were being done, but he felt it had to be done to get things done.”

Prosecutors urged U.S. District Judge Peter J. Messitte to send a message by sentencing Colton to a jail term of at least two years.

“Just as no public official is above the law, the private citizen who pays the bribes to keep the cycle of corruption going must also face the consequences of participating in public corruption and facilitating the abuse of public office for private gain,” Assistant U.S. Attorney James A. Crowell wrote in a memo filed before the hearing at the federal court in Greenbelt.

Colton, 64, built his successful real estate business over nearly three decades. Before he was charged in 2010, he made more than $650,000 a year, according to the government filing, and still owns “millions of dollars in real estate, jewelry and household furnishings.”

He pleaded guilty more than three years ago to an extortion conspiracy and to lying on campaign finance reports filed with the Federal Election Commission. Prosecutors said Colton and his associates spent $400,000 to $1 million doing favors for Jack Johnson and others in county government. In addition to gifts of money and travel, Colton and his associates illegally funneled thousands of dollars in campaign donations to federal, state and local officials.

In exchange, prosecutors said, officials repeatedly took action beneficial to a development that was slated to produce housing, retail and commercial space near the Greenbelt station.

After Colton was initially approached by the FBI in 2008, he said Tuesday that he “worked hand-in-glove” with investigators and offered his full cooperation. Colton’s attorney and the government declined to elaborate after the hearing on the nature of the developer’s cooperation or what, if anything, came from it.

Prosecutors, however, recommended some leniency for Colton in light of his cooperation, his age and his health problems, including high blood pressure.

Standing at the courtroom lectern, Colton became emotional when he acknowledged what he called his “horrible mistake.”

When approvals from county officials for his project stalled, Colton said he acted improperly to protect his investors.

“It’s important for me to own it,” he said. “I’m more than ashamed and embarrassed for what I did.”

Colton already has served more than three years in prison after an earlier conviction on conspiracy and bank fraud charges related to other Maryland development projects.

Among Colton’s partners, Patrick Q. Ricker was sentenced to one year in prison. Karl Granzow, a former deputy fire chief who was a business associate and close friend of Ricker’s, was sentenced to 18 months.

Johnson, who prosecutors say began shaking down developers almost immediately after taking office in 2002, is serving a seven-year sentence in a North Carolina prison facility that Colton requested to be assigned to in court on Tuesday.

Johnson’s wife, Leslie, served a one-year term after pleading guilty to destroying evidence, most memorably by flushing a $100,000 check down the toilet and stuffing $79,600 in her bra as federal agents knocked on her door in fall 2010.

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