A month before he left office, Jack B. Johnson, Prince George’s County’s top elected official, called his friend Mirza Baig and told him that he was working on the doctor’s “stuff as we speak.”

“I appreciate that,” replied Baig, a noted internist and real estate developer. “Do you want to stop by the office this afternoon? I have some medical reports for you.”

Johnson drove to Baig’s Largo office that November day and picked up the “medical reports” — a $5,000 bribe. The “stuff” was the county executive’s help in getting federal money for Baig’s building project.

Johnson knew Baig was talking in secret code. But so did the FBI.

Federal agents had been investigating widespread corruption in the county for years — and listening in on Johnson’s calls for months. By October, Baig was helping the government. And in November, Johnson was arrested, the central player and big fish in a still-spiraling pay-to-play scandal.

Last week, Johnson pleaded guilty to two felony charges, admitting in court that he took more than $400,000 in bribes while he ran Prince George’s, one of the Washington area’s largest suburban counties. Johnson’s plea was the nadir of a public career that spanned 16 years at the heights of power in Prince George’s, first as the county’s top prosecutor and then two terms as county executive.

Prosecutors also unsealed a treasure-trove of documents that detail how Johnson, a Democrat, used his office to enrich himself, his friends and his wife, Leslie, who was mounting what would be a successful run for County Council. The documents shed new light on an ongoing corruption case that stretches 11 years, potentially implicating county administration officials, political candidates, and members of the County Council and school board.

U.S. Attorney Rod J. Rosenstein said the investigation won’t end until “the crimes are over.” Last week, he revealed that guilty pleas had been secretly entered by Baig and two others — James E. Johnson, a former county housing director, and Patrick Q. Ricker, a real estate developer.

The plea deals and court documents provide a window into a political culture of illegal deal-making, one in which Ricker and his associates, in exchange for help on projects, provided public officials with “money, trip expenses, meals, drinks, hotel rooms, airline tickets, rounds of golf, sexual services, employment, and monetary and in-kind campaign contributions,” according to prosecutors.

As Prince George’s faced a searing financial crisis, and Jack Johnson approached the end of his final term, the documents show that the county executive was focused on a more personal agenda than the county’s problems.

At moments, he was Mr. Fix-it, promising to make sure a supporter’s restaurant passed a county health inspection and using his influence to land Baig’s friend a job. He made phone calls into the bowels of the county bureaucracy to help Baig’s real estate project.

“I will jump on it immediately for you,” Johnson told Baig after the doctor complained that his project had not yet received a $1.7 million federal subsidy.

Other times, Johnson was the puppeteer, ordering associates to contribute money to his wife’s campaign and promising that the legacy would continue as she emerged as a powerful player on the County Council.

“What I’m tryin’ to do is get Leslie over [to] zoning,” Johnson told Baig in November. “Zoning is huge in the county . . . and then we’re gonna work together so you shouldn’t have any problems.”

Leslie Johnson, now a council member, is charged with evidence tampering after she was accused of stuffing the bribe money in her bra as the FBI closed in. Her case is pending.

The art of corruption

Jack Johnson served as a kind of sage in the art of corruption, advising another public official to take two years to put away “a couple of hundred thousand dollars” in cash. “Then you can go and, ah, and you, you get your little retirement,” he continued. “You just want something nice in South Carolina.”

The cast of characters implicated so far in the scandal are well-known in county political and business circles.

Ricker, a garrulous, swashbuckling businessman, has long had a reputation for cozying up to politicians. At a holiday party in 2003, a year after Johnson took office, Ricker made a show of getting down on one knee and bowing before the county executive. Ricker assigned a server to follow Johnson around the party, filling his wine glass whenever it emptied.

From 1997 to 2008, according to his plea agreement, Ricker flouted campaign finance laws by giving at least $400,000 to “straw donors,” who then funneled the funds to the developer’s favored candidates. Ricker treated public officials to a number of lavish meals, such as a $1,381 dinner at a Ruth’s Chris Steak House in August 2007.

But everything changed for Ricker in October 2008 when the FBI raided his office and several others. By the end of the year, he was cooperating with authorities. From June 2010 to October, under the direction of the federal investigators, he gave James Johnson, the county housing director, $30,000 in bribes.

Baig, 67, and Jack Johnson were introduced in the 1980s by Henry T. Arrington, a patient of Baig’s who would become Johnson’s campaign chairman. Baig later hosted Johnson fundraisers at his Burtonsville home, introducing him to other Pakistani doctors who would become campaign contributors.

Short and balding, Baig is described by friends as mild-mannered and religious, often interrupting meetings to pray. While managing his medical practice, he became a developer and, with Johnson, bought property in Laurel in 1992. From 2000 to 2005, Baig and his family contributed $11,800 to Johnson’s political campaigns. The doctor hosted a fundraiser in 2005 at which the county executive raised $27,000.

Altogether, according to the documents, Baig paid at least $400,000 in bribes to Jack Johnson and James Johnson, beginning in 2003.

Over the next six years, Baig won at least three development projects from the Johnson administration. By 2010, the men were enmeshed in a variety of deals, with Jack Johnson helping Baig procure federal funds for an Upper Marlboro development. The doctor, in turn, agreed to purchase an investment property Johnson owned in the District.

In phone conversations intercepted by the FBI, Johnson and Baig carried on negotiations.

In early February 2010, Johnson called and reminded the doctor that he had gotten Baig’s friend a job at a hospital.

“That’s excellent,” Baig responded, adding that the woman’s life would be changed forever.

“That was a big one,” Johnson agreed.

In May, Baig complained to Johnson that a federal subsidy he was counting on for a development project hadn’t come through, identifying the county employee he saw as the obstacle.

“I’ll give a call,” Johnson said. “Not her, but I’ll call, um, the bosses.”

Twelve days later, Johnson reassured Baig that he had not forgotten his promise, saying: “I’ll try to get it done this week coming up.” But the county executive was irked by the doctor’s persistence, telling an associate that Baig is “bugging the [expletive] out of me.”

In late June, Johnson called Baig, saying, “Me and you, never quite finished, worked out those, that project the, ah, with the hospital. Remember the one with the, ah, lady that, um, got the job.”

Baig assured Johnson that it would be settled “sometime next week” — a reminder that the doctor still owed him a $150,000 payment.

A check for $100,000

In mid-August, Baig gave Johnson $12,000 in cash. Nearly two weeks later, the doctor handed the county executive $8,000. On Sept. 9, Baig gave Johnson a check for $100,000.

In October, Baig began working with federal investigators. He told officials “every excruciating detail going back years,” said Paul Kemp, Baig’s attorney.

On Nov. 5, Baig handed Johnson $5,000 after inviting him to pick up his “medical reports.” A week later, he gave the county executive $15,000 in a meeting that was interrupted by federal agents, who searched Johnson and found the cash.

The agents allowed Johnson to leave. Driving home, the county executive took a frantic call from his wife, who said someone was pounding on their front door. Sensing what was about to happen, he ordered her to destroy the $100,000 check Baig had given him and to stuff nearly $80,000 in cash in her bra and panties.

“They’re saying ‘FBI,’ Jack,” Leslie Johnson said as the agents beat on the door.

“I know,” he replied. “Baig set me up.”

Staff writer Ovetta Wiggins contributed to this report.