Federal investigators are probing the circumstances surrounding former state senator Phillip P. Puckett’s resignation last week, which gave Republicans control of the Virginia Senate and resulted from a deal with Republican lawmakers involving a job for Puckett and a judgeship for his daughter.

Two people with knowledge of the investigation confirmed that federal investigators have interviewed officials and sought documentation related to Puckett’s resignation and the job offers.

The investigation was first reported Wednesday by the Richmond Times-Dispatch.

Puckett, a Democrat from rural Russell County, caused a firestorm when he resigned and prepared to take a job at the Virginia Tobacco Indemnification and Community Revitalization Commission, which state delegate and commission chairman Terry G. Kilgore (R-Scott) confirmed at the time had been arranged for the senator. Puckett said at the time that no quid pro quo was involved.

Puckett’s departure from the Senate quickly led to the end of a budget showdown over whether to expand Medicaid under the Affordable Care Act; last Thursday, lawmakers passed a budget without Medicaid expansion. Gov. Terry McAuliffe must act on the bill by Sunday.

House Minority Leader David J. Toscano (D-Charlottesville) called for an investigation in a floor speech during the budget deliberations last week. On Wednesday, he said that he didn’t know that one had been launched.

“I’ve not been contacted by the FBI or the U.S. attorney’s office, so I’m not aware of the nature of the investigation nor the extent, but I do think an investigation is appropriate under the circumstances because it is totally baffling that someone with the integrity of Phillip Puckett would resign under this set of circumstances,” he said.

Calls to the U.S. Attorney’s Office for the Western District of Virginia, the Virginia Attorney General’s Office, Puckett and Kilgore were not immediately returned.

Toscano called an investigation “perfectly appropriate” because of what he called the strange timing of the resignation.

“There was no reason for him to leave at this point in time. Unless there was some suggestion that he was being offered something in exchange,” he said.

In the end, Puckett withdrew his name from consideration for the tobacco commission job.

At the time, Kilgore disputed the notion that Puckett was resigning in exchange for the tobacco commission job, but he said the resignation made Puckett available to take the position, which involves awarding economic development grants funded by the national tobacco litigation settlement.

Others, including Attorney General Mark R. Herring (D) said that Puckett’s actions, while regrettable for their political impact, would not prompt an investigation by his office because of limits to its statutory authority. He said if any evidence of criminal wrongdoing arose, it would be up to local or state police or federal authorities to investigate.

Virginia politics-watchers, after all, have seen this one before: A long-serving Democrat from an increasingly red district gives up his Senate seat to take a state job, handing control of the evenly divided chamber to the GOP.

It happened in 1997, when then-Gov. James S. Gilmore III (R) turned a Democratic senator from Loudoun County, Charles Waddell, into his deputy transportation secretary and thereby gave the GOP a 20 to 19 edge.

Then, as now, Democrats were furious. “Job Offers Called GOP Plot,” a headline in The Washington Post read at the time.

But the reaction this year seemed particularly sharp given that state legislators, reeling from a gifts scandal involving former governor Robert F. McDonnell (R), went into this year vowing to improve ethics in Richmond.

McDonnell and his wife, Maureen, are scheduled to go to trial next month on federal corruption charges stemming from their acceptance of more than $165,000 in loans and luxury gifts from Richmond-area businessman Jonnie R. Williams Sr., whose dietary supplement they helped promote. The McDonnells have pleaded not guilty.

Rosalind S. Helderman and Jennifer Jenkins contributed to this report.