In this file photo, Phillip P. Puckett (D) poses a question during a public hearing on a bill in Richmond. (Steve Helber/AP)

Federal prosecutors will not pursue criminal charges in the resignation of a state senator who quit amid job talks, quietly closing an episode that further tarnished Virginia’s proud reputation for clean government.

The surprise exit of Sen. Phillip P. Puckett (D-Russell) in June threw control of the evenly split state Senate to Republicans, who had discussed giving his daughter a judgeship and Puckett himself a job on the state tobacco commission.

The move thwarted the chief legislative priority of Gov. Terry McAuliffe (D) and created a sense that the commonwealth — then girding for the lurid corruption trial of a once-popular governor and his wife — had sunk to ethical lows more commonly associated with the likes of Louisiana or Illinois.

That feeling only intensified as it was revealed that Democrats, who had accused the GOP of dangling jobs to lure Puckett out of the Senate, had proposed potential jobs in a failed bid to get him to stay.

In a letter sent Friday declaring that the six-month Puckett investigation would result in no charges, federal prosecutors closed the matter legally but also revealed for the first time that McAuliffe’s chief of staff had been drawn into the probe.

Timothy J. Heaphy, U.S. attorney for the Western District of Virginia, addressed the letter to four people who had been interviewed in the course of the investigation, according to several people with direct knowledge of the matter. The four were Paul Reagan, McAuliffe’s chief of staff; and attorneys for Puckett, Puckett’s son, Joseph, and Del. Terry G. Kilgore (R-Scott).

“After reviewing facts gathered during the investigation, considering potentially applicable statutes, and consulting with the Public Integrity Section at the Department of Justice, we have decided not to pursue federal charges for acts surrounding Senator Puckett’s resignation,” Heaphy wrote.

McAuliffe’s office has never acknowledged that investigators had contacted Reagan about the case. On Friday, spokesman Brian Coy declined to comment, as did Reagan.

Puckett resigned while discussing a judgeship for his daughter and a job for himself on the GOP-controlled state tobacco commission. Puckett and Kilgore, who was chairman of the commission, said there was no quid pro quo, but the resignation set off howls from Democrats and triggered a federal probe.

The investigation threatened to spread after it was revealed that Sen. Mark R. Warner (D-Va.) and Reagan also suggested potential jobs to dissuade Puckett from leaving. The letter was not addressed to Warner or anyone representing him. His spokesman declined to comment except to say that authorities had never contacted the senator about the matter.

“Obviously we’re extremely pleased with the decision, but it’s a shame that Phil had to go through this torture for six months,” said Puckett’s attorney, Thomas J. Bondurant. “From Day One it was absolutely clear there was no criminal act.”

Said Kilgore’s lawyer, Thomas T. Cullen: “Delegate Kilgore fully cooperated [with authorities] from the outset, and we’re thrilled that he could help them reach the conclusion that criminal charges were not warranted.”

Joseph Puckett had been drawn into the case because Warner called him to discuss potential jobs that might keep his father from quitting the state Senate.

The younger Puckett’s attorney, Charles E. “Chuck” James Jr., said he was pleased that prosecutors had issued the letter so that people who had been investigated could clear their names.

“Everyone thinks all public officials are corrupt and crooked,” James said. “It’s nice to be able to say, ‘You may not like it, but there’s no crime here.’ ”

Puckett’s exit swung control of the Virginia Senate to Republicans at a time when McAuliffe was relying on Senate Democrats to approve his top goal of expanding Medicaid under the Affordable Care Act.

Puckett and Kilgore said at the time that the senator was resigning primarily to clear the way for his daughter to become a judge. The House had twice confirmed Martha Puckett Ketron, an interim juvenile court judge, to a six-year term. But the Senate, citing an anti-nepotism policy, declined to act while her father was in office.

Only after deciding to quit did Puckett have any serious discussions with Kilgore, a fellow Southwest Virginian and friend, about working for the commission, lawyers for Puckett and Kilgore have said.

The job deal fizzled, however, when Puckett withdrew from consideration shortly after news of his resignation broke in early June. His daughter’s judgeship stalled, too, though Republicans say it could come up for a vote in January.

Reagan, who suggested that Puckett’s daughter might head a state agency, has apologized for his “overzealous” effort to keep Puckett from resigning from the evenly split state Senate. McAuliffe has said he was unaware of his chief of staff’s actions until months later.

Warner acknowledged that he “brainstormed” about a federal judgeship or corporate job for Puckett’s daughter but insisted that he never offered a specific job.