State Sen. Mark Herring, a Loudoun Democrat running for attorney general, is calling for a federal investigation into financial dealings between Virginia supplement maker Star Scientific Inc. and the state’s two top Republicans, Gov. Robert F. McDonnell and Attorney General Ken Cuccinelli II.

Herring announced Thursday that he has sent a letter to the public integrity section of the U.S. Department of Justice seeking an inquiry.

“The people of Virginia need to know what the facts are,” Herring said. “They need to know if any laws were broken. Until a fair and independent investigation is done, we’re not going to have an answer to those questions.”

Herring based his request on recent news articles about connections between Star and its chief executive to McDonnell and Cuccinelli. Star, a former cigarette maker that makes a supplement and facial cream with a chemical found in tobacco, is the subject of a federal securities investigation and two shareholder lawsuits.

The company has lost money for the past 10 years, but the firm and Williams donated generously to the Republicans, providing personal gifts, rides in a corporate jet and campaign contributions.

Virginia Sen. Mark Herring (D), who is running for attorney general, has requested a federal investigation into the matter. (Courtesy Mark Herring)

McDonnell’s office said it had no comment on Herring’s announcement. Cuccinelli’s campaign said it was a political stunt intended to help his Democratic opponent in the governor’s race, Terry McAuliffe.

“No matter how hard the McAuliffe campaign might try, there is no conflict of interest involving the attorney general, period,” said Cuccinelli spokeswoman Anna Nix. “Virginians are not buying this shameful ploy.”

The Washington Post reported recently that Star chief executive Jonnie R. Williams Sr. paid the $15,000 catering bill at the wedding of McDonnell’s daughter Cailin. The governor has said there was no need to disclose the gift because it was a present to his daughter, not him.

Herring suggested that the payment could be construed as a gift to the governor, given that, as the The Post subsequently reported, McDonnell personally signed the catering contract and put down an $8,000 deposit, part of which was later refunded to first lady Maureen McDonnell.

“He had been obligated on the contract and this payment relieved him of the obligation to make the payment,” Herring said.

The Post also reported that Cuccinelli initially failed to disclose that he held more than $10,000 in Star stock in 2011, the same year the company filed a lawsuit challenging the state’s tax assessment of its Mecklenberg County tobacco barns. Cuccinelli has said the error was an oversight, one he corrected in 2012, well before recent media scrutiny of Star.

Cuccinelli had said he was not personally involved in the ongoing tax case, but last week, amidst criticism from Democrats, he handed the matter off to a private firm.

In addition to a federal inquiry, Herring called for the reform of Virginia’s ethics laws, which allow officeholders to accept unlimited gifts as long as they disclose any worth more than $50. Gifts to immediate family members do not need to be disclosed.

Herring said that gifts to close relatives should have to be disclosed and that there should be a limit on the value of gifts given. He did not suggest a specific dollar limit, but suggested that it should be well short of the amount Williams paid for Cailin McDonnell’s wedding.

“When a gift of $15,000 is showered on a public official and that company has business in front of the state, it certainly raises questions about whether there might be some quid pro quo,” Herring said. “And that’s the kind of thing that reforming our ethics law would get at.”

Rosalind S. Helderman contributed to this report.

This post has been updated and corrected to make clear the Herring said the catering payment could be construed as a gift to Gov. Robert F. McDonnell, not his daughter.