Alaska’s top election official is investigating a GOP Senate candidate who shares the same name as incumbent Sen. Dan Sullivan (R-Alaska), citing “credible allegations” that he entered the race to confuse voters.

Lt. Gov. Nancy Dahlstrom (R), who oversees elections in Alaska, said Monday that her office is investigating Daniel J. Sullivan Jr. — who goes by “Dan Sullivan” on his campaign website — to determine whether he may appear on the Aug. 18 primary ballot.

“This Division must determine whether your declaration of candidacy was properly filed with good-faith intention to serve,” she wrote in a June 8 letter to Sullivan. “I’m troubled by the allegation that you filed for office in coordination with another campaign with the intention of confusing Alaskan voters in a way that will benefit one candidate over another.”

If true, she wrote, the allegations “would amount to not only deception of voters but diminish the rights of another candidate.”

Dahlstrom requested that Sullivan submit a sworn affidavit answering several questions, including whether he was previously affiliated with the Republican Party, if he’s always used the nickname “Dan” and to describe the design process behind his campaign website and logo.

The former U.S. Forest Service employee and elementary school teacher from Petersburg filed to challenge the incumbent Republican senator last month.

Republicans have alleged his candidacy is part of a coordinated effort between the challenger and Democratic rivals to siphon votes from Sen. Sullivan by exploiting the fact that the two Republican candidates share identical names.

The investigation stems from a letter sent to Dahlstrom by the National Republican Senatorial Committee (NRSC), attempting to block Sullivan from appearing on the ballot and urging her to investigate him.

In the letter obtained by Politico, NRSC alleged that Sullivan coordinated with Democratic strategist Amber Lee and others to “proactively confuse Alaskan voters and rig the voting system” to benefit the senator’s main rival for the seat, former Rep. Mary Peltola (D).

The Hill has reached out to the Sullivan Jr. campaign, Sen. Sullivan’s office and Lee for comment.

The challenger denied the claims in a telephone interview with the Associated Press, saying he had been considering a bid for Senate for more than a decade and that he has had zero contact with Peltola’s campaign.

“I have every right to run for whatever office I’m qualified for, and I’m qualified for this office,” he said.

Sen. Sullivan last week threatened a lawsuit to get to the bottom of the matter.

“Everybody in Alaska knows I’m Dan Sullivan-R. So he’s trying to do that. Why?” he said to reporters, of the other Dan Sullivan. “He’s not an R. He’s purposely trying to trick my constituents to rig the election for Peltola.”

While Peltola did not immediately respond to The Hill’s request for comment, a spokesman for Peltola has publicly denied any involvement in the Sullivan situation.

Harry Child, a spokesman for her campaign, told the Associated Press that it “has no involvement in either Sullivan campaign,” and executive director of the Alaska Democratic Party Jenny-Marie Stryker said her organization “is in no way affiliated with either Dan Sullivan.”