Virginia Democrats stepped up their request for an independent investigation of Attorney General Ken Cuccinelli II’s intervention in a legal dispute over natural gas royalties by going to one of the two state officers who has the authority to initiate such a probe: Cuccinelli.

Del. Mark Sickles (D-Fairfax), chairman of the Minority Caucus in the House of Delegates, said Friday that he visited the attorney general’s Northern Virginia regional office to drop off a letter urging Cuccinelli to ask for an independent investigation of his own agency by the Inspector General Office. Other Democrats visited other attorney general offices in the state with the same request.

Democrats said they called on Cuccinelli, who is running for governor, to initiate the review because state law says that the inspector general can investigate an elected official for possible criminal violations only at the request of the governor, the attorney general or a grand jury.

Democrats said the public has a right to know whether Cuccinelli’s office violated laws or ethics when one of its senior attorneys collaborated with two Pennsylvania-based energy companies sued by Virginia landowners, who say the companies cheated them out of their natural gas royalties. One of the companies is part of a corporation that has given more than $111,000 to Cuccinelli’s gubernatorial campaign since 2010.

Cuccinelli’s campaign dismissed the group of Democratic couriers as a political stunt to keep a manufactured controversy going.

On Friday, Brian J. Gottstein, a spokesman for the attorney general’s office, said Cuccinelli had used his office to push for legislative reforms in 2011 that could have accelerated the resolution of the disputed claims and therefore allowed rightful owners of the royalties to receive their money.

Among other things, the draft bill would have allowed the Virginia Gas and Oil Board to use hearing officers to make speedier determinations of ownership of natural gas royalties. And it would have levied fees on energy companies to cover the cost of the hearings, Gottstein said.

“This bill alone should prove that the AG was supportive of the property owners,” Gottstein said in an e-mail.

Gottstein also said Cuccinelli had asked Sen. Phillip P. Puckett (D-Russell) to sponsor the bill, but the senator declined. Puckett this week was the first to call for an investigation of Cuccinelli’s handling of the legal dispute. He could not be reached for comment.

Cuccinelli and the companies have denied wrongdoing. Cuccinelli has said that a senior attorney in his office discussed legal strategy with the energy companies only to defend the Virginia Oil and Gas Act and its method of handling competing claims to royalties generated from the production of coal-bed methane.

The companies — EQT Production Co. and CNX, which is a unit of Consol Energy — say they have paid the landowners what they were due or properly laid aside part of those disputed proceeds into escrow, as required by the Gas and Oil Act. The escrow account now holds about $28 million.

The cooperation between the attorney general’s office and the defendants came to light in a U.S. magistrate’s opinion analyzing whether several lawsuits filed by the landowners should be given status as a class action.

“Based on media reports and the expression by a federal magistrate judge that this was unusual, we need to get to the bottom of that,” Sickles said Friday. “When you seek a $100,000 contribution from someone that wants your help as attorney general, that doesn’t pass the smell test.”

Anna Nix, a spokeswoman for Cuccinelli’s campaign, suggested that the real reason for the Democrats’ hand-delivered letters was that the GOP had identified a potential conflict of interest with Puckett, who is a vice president at the bank that manages the escrow account with the disputed funds. Puckett has acknowledged that his bank manages the money but denied any such conflict of interest and invited anyone to request that the inspector general examine his conduct in the matter.

Republicans also accused the campaign of Terry McAuliffe of distorting the attorney general’s role in the legal dispute over royalties for political reasons. The GOP said that McAuliffe, having previously criticized the coal industry, is now trying to appear as a friend to southwest Virginia. They noted that PolitiFact Virginia on Friday rated McAuliffe’s shifting stance on coal as a “full flop.”

“Having failed miserably to credibly make this dishonest attack with Phil Puckett, Terry McAuliffe’s campaign has moved on to another surrogate to advance its fictitious political narrative,” Nix said. “If Terry McAuliffe wants to debate who has stood up for everyday, hardworking Virginians versus who has made a career of stepping on workers’ backs for profit, he should accept the attorney general’s debate challenge in southwest Virginia.”

On Monday, Puckett, in an e-mail, asked the inspector general to investigate Cuccinell’s handling of the natural gas case. In a reply e-mail, an employee in the Office of Inspector General Doug Bevelacqua acknowledged receipt of Puckett’s request and said the office would “look into it.”

Several calls to the inspector general seeking comment have not been returned.