News of another corruption investigation in Virginia has many public officials wondering whether federal prosecutors are subjecting elected leaders in a state with scant history of political graft to higher standards than in the past.

“I wish they’d send a memo out,” said Del. David B. Albo (R-Fairfax), one of several legislators who asked why federal investigators were probing last week’s surprise resignation of then-state Sen. Phillip P. Puckett, a Democrat from Southwest Virginia.

“I’m just not getting what the investigation is about,” he said. “This has happened a number of times in the past.”

Federal investigators this week interviewed officials and sought documents in connection with Puckett’s exit, which handed Republicans control of the Virginia Senate at a critical time and was connected to job prospects for Puckett and his daughter.

The resignation enraged Democrats, who accused Republicans of bribing Puckett to leave the Senate as a way to break a deadlock over the state budget and Medicaid expansion. Puckett said there was no quid pro quo but withdrew his name from consideration for a top job with the state tobacco commission.

Even some of Puckett’s most prominent critics expressed mixed feelings about a federal inquiry into a matter that many considered unseemly but not criminal.

When word of the federal investigation leaked Wednesday night, House Minority Leader David J. Toscano (D-Charlottesville) said it was “perfectly appropriate.” But he expressed some discomfort a day later, noting that when he had called for an investigation on the House floor last week, he was urging the state’s inspector general to find out what happened, not seeking a criminal inquiry.

“It is a little troubling to think about this as a criminal investigation, because it’s so hard to figure out what people’s motives are in this,” Toscano said. “But the world has changed so much, and everything is so much more under the microscope. You just have to be so careful, and you have a special responsibility to maintain the public trust.”

As legislators reacted to the probe, new details emerged Thursday about what investigators were looking for. According to two people with direct knowledge of the investigation, a federal subpoena issued by a grand jury Wednesday directed the Tobacco Indemnification and Community Revitalization Commission, its staff and board members to supply any written communications related to job offers to Puckett and his daughter. The subpoena, issued by a federal grand jury for the Western District of Virginia, seated in Abingdon, also directs a top commission staff member to testify Tuesday.

Also Thursday, news emerged that one public official involved with Puckett’s job prospects had retained a prominent former federal prosecutor to represent him in the matter. State Del. Terry G. Kilgore (R-Scott), who is also the chairman of the tobacco commission, is being represented by Thomas Cullen, a former assistant U.S. attorney in the Western District, where the Puckett investigation is taking place.

Cullen confirmed his role and denied that his client had done anything improper or was involved in the investigation. “Neither the FBI nor the U.S. attorney’s office has contacted Delegate Kilgore in connection with this investigation,” Cullen said. “He’s done absolutely nothing wrong and has nothing to hide.”

A spokesman for U.S. Attorney Timothy J. Heaphy declined to confirm or deny an investigation was underway.

Puckett stepped down June 9 with the stated purpose of clearing the way for his daughter, Martha Puckett Ketron, to be appointed a juvenile court judge. His service in the Senate was a well-known impediment to his daughter’s appointment because the Senate has a policy against seating the relatives of sitting legislators. The House, which does not share that policy, had twice approved the appointment, which local Circuit Court judges have given her on a temporary basis.

Puckett and Kilgore disputed the idea that he was resigning to accept a job with the commission.

When news of Puckett’s resignation broke, Kilgore confirmed that the commission’s executive committee was expected to meet and consider appointing him two days later. But Kilgore said the resignation merely made Puckett available to take the position, which involves awarding economic development grants funded by the national tobacco litigation settlement.

But the timing — and the power shift his departure caused in the Senate — looked fishy to many, even in the state Capitol, where Puckett had been held in high esteem. For that reason, some welcomed the investigation even as they found it unsettling.

“We ought to be troubled. We ought all tremble,” said Sen. Creigh Deeds (D-Bath). “I’ve read some pretty nasty speculation. We ought to fear people talking like that. ... When you’re elected to office, your public actions ought to be beyond reproach.”

There is a heightened sensitivity about ethics in Richmond after the indictment in January of former governor Robert F. McDonnell (R) and his wife, Maureen, on federal corruption charges. Legislators imposed limits on some gifts to public officials and closed some loopholes in state ethics laws this year, but they still left themselves free to accept vacations, meals and other “non-tangible” gifts of unlimited value.

Despite having some of the loosest gift laws in the country and campaign-finance laws that allow for limitless political donations, Virginia has long enjoyed a reputation for clean government. McDonnell is the first former Virginia governor to be indicted, although Democrat Charles S. Robb was investigated by a grand jury.

The state’s proud history has not prevented legislators from wheeling and dealing for jobs. In 1997, then-Gov. James S. Gilmore III (R) turned a Democratic senator from Loudoun County, Charles L. Waddell, into his deputy transportation secretary, a move that gave the GOP a 20-to-19 edge in what had been an evenly divided Senate.

Gilmore also appointed a Democrat to head the Department of Conservation and Recreation, creating an opening for a Republican to win a seat in the House.

Those moves set off howls from Democrats but no criminal probes.

More recently, Phillip A. Hamilton, a former high-ranking member of the Virginia House of Delegates, was sentenced to nearly a decade in federal prison for bribery and extortion. In May 2011, a jury found that the Newport News Republican had steered a half-million-dollar earmark to Old Dominion University and secured a $40,000-a-year position at the Norfolk university in return.

Critics said the timing of Puckett’s departure is what sets his case apart, because it appeared to hand Republicans victories in two legislative battles — the budget and Medicaid expansion — in addition to a broader advantage in the Capitol.

Even so, legal experts said building a public corruption case against Puckett or Kilgore could be an uphill climb.

In 2010, the Supreme Court decided that the government could not prosecute legislators or government officials for what is known as “honest services fraud” simply because they participated in a self-dealing, conflict-of-interest arrangement.

Prosecutors had to prove that the officials took bribes or kickbacks as part of a quid pro quo, the court decided. Proving that quid pro quo requires prosecutors to show that the public official made or promised to make “official acts” in exchange for the bribes or kickbacks.

The question for Puckett and Kilgore and those investigating the arrangement, experts said, is this: Is resigning one’s office an “official act”?

“It’s a stretch, because I think it’s more of an abdication than an act,” said Andrew T. Wise, a defense lawyer at Miller & Chevalier who represented a lobbyist connected to Jack Abramoff. “I would hate to be the line prosecutor trying to sell this to my supervisor.”

But such a prosecution is not impossible, Wise said. Say, for example, a state legislator took $5,000 to abstain from voting on a matter when his or her vote would have broken the tie. Would that constitute honest services fraud, and is that so different from Puckett’s conduct?

“You could cobble together an argument,” Wise said.

Edward T. Kang, a former federal prosecutor now at the Alston & Bird firm, said it is likely that agents are looking for evidence of “official acts.” As to whether the resignation itself could be the official act, Kang said, “That would be novel. I’ve definitely never heard of anything like that.”