LAS VEGAS >> Nevada’s attorney general is investigating six Republican electors who submitted a document to Congress falsely declaring Donald Trump the winner of the 2020 presidential election, a person with knowledge of the case said Wednesday.

It was not immediately clear if the ongoing probe was a criminal or civil matter. But the probe adds to official scrutiny of fake electors in several swing states won by President Joe Biden in 2020, including investigations in Georgia, Michigan and Arizona. Fake electors were charged in Georgia and Michigan, and Trump faces charges both in Georgia and in a federal investigation of his conduct related to the Jan. 6, 2021 Capitol riot.

The person was not authorized to speak publicly and spoke to The Associated Press on condition of anonymity. Politico and NBC News first reported the existence of the investigation.

Attorney General Aaron Ford, a Democrat, did not respond Wednesday to messages. He has said in the past that his office was cooperating and participating with a U.S. Justice Department investigation of the efforts to keep Trump in office. He told the Democratic Attorneys General Association last January he feared that making any comment would be seen as partisan.

Nevada Gov. Joe Lombardo, a Republican, vetoed a bill last June passed by the Democratic-led Legislature that would have made it a felony to falsely certify that a losing candidate has won an election.

Among those who served as false electors in 2020 are current state GOP chairman Michael McDonald, national party committee member Jim DeGraffenreid, Clark County party chair Jesse Law and Shawn Meehan, a national and Douglas County committee member. All declined to comment.

McDonald introduced Trump at an October rally in Las Vegas and pushed for the Nevada GOP to hold a nominating caucuses change seen by many Republicans as benefiting the former president. The GOP caucuses will take place Feb. 8, two days after a state-mandated primary.

Efforts by AP to reach the other two fake electors, Durward James “Jim” Hindle III and Eileen Rice in northern Nevada, were not successful.

“These individuals all have no comment,” said Brian Hardy, an attorney involved in the case.

The six electors gathered on Dec. 14, 2020, in Carson City and agreed to send an electoral certificate to Congress in a bid to cast Nevada’s six electoral votes for Trump and keep the former president in power, according to transcripts of closed-door testimony before the U.S. House committee that investigated the Jan. 6 attack that disrupted the tally of electoral votes.

Trump lost Nevada by about 30,000 votes to Biden. The state’s Democratic electors certified the results in the presence of Nevada Secretary of State Barbara Cegavske, a Republican whose defense of the results as reliable and accurate led the state Republican Party to censure her. Cegavske later conducted an investigation that found no credible evidence of widespread voter fraud in the state. Term limits barred her from seeking reelection.

McDonald and DeGraffenreid were among those who testified before the House committee.

Government and outside investigationshave uniformly found there was no evidence of widespread voter fraud that could have swung the election from Biden. Trump has continued to spread falsehoods about the 2020 election.