Michigan Attorney General Dana Nessel charged 16 Republicans who falsely claimed to be the state's 2020 presidential electors with forgery and other felonies Tuesday, bringing the first criminal prosecution against Trump electors as investigations over attempts to overturn election results intensify across the country.

Nessel, a Democrat, brought the charges against former state Republican Party co-chairwoman Meshawn Maddock and 15 others who submitted official-looking paperwork to the federal government asserting they were casting the state's electoral votes for President Donald Trump. Joe Biden won Michigan, and courts swiftly threw out lawsuits claiming Trump was the true winner of the state.

The charges stem from a state investigation that is separate from a federal probe by special counsel Jack Smith into attempts to reverse the 2020 results. Trump on Tuesday said he had received a Justice Department letter telling him he was a target of Smith's investigation.

After Trump lost, Republicans in seven states that Biden won — Arizona, Georgia, Michigan, Nevada, New Mexico, Pennsylvania and Wisconsin — filed paperwork claiming to be their states' true electors.

The GOP electors in Michigan are the first to face criminal charges. In addition to Smith's investigation, prosecutors in Arizona and Georgia are looking into the GOP electors in their states and civil lawsuits have been filed against electors in Michigan and Wisconsin.

In Michigan, each Trump elector was charged with eight criminal counts, including forgery, conspiracy to commit forgery and election law forgery. Some of the counts carry sentences of up to 14 years in prison.

In an online video announcing the charges, Nessel noted the 16 Republicans had submitted paperwork to the Senate, National Archives and elsewhere claiming to be the state's official electors. "That was a lie," she said.

"Undoubtedly, there will be those who claim these charges are political in nature," Nessel said. "But where there is overwhelming evidence of guilt in respect to multiple crimes, the most political act I could engage in as a prosecutor would be to take no action at all."

Nessel investigated the Republican electors after the 2020 election and last year referred their activities to federal prosecutors. After being sworn in for a second term in January, she announced she was reopening her own probe of the GOP electors because she didn't know what federal prosecutors planned to do with the case. At the time, she said the House committee that investigated the Jan. 6, 2021, attack on the Capitol had turned up strong evidence to support charging the Trump electors from Michigan.

In addition to Maddock, charges were issued against Kathy Berden, William "Hank" Choate, Amy Facchinello, Clifford Frost, Stanley Grot, John Haggard, Mari-Ann Henry, Timothy King, Michele Lundgren, James Renner, Mayra Rodriguez, Rose Rook, Marian Sheridan, Ken Thompson and Kent Vanderwood.

Attorneys for those who were charged did not immediately respond to requests for comment, but Thompson told Michigan news site MLive that the charges were baseless. "It is an attempt to put pressure on the ill-informed and feed the narrative to a population that is woefully lacking knowledge of the processes of our government," he said.

Electors in every state met on Dec. 14, 2020, to cast their votes for president. Since Biden won Michigan by more than 150,000 votes, his electors gathered at the state capitol to cast their ballots. Republicans in Michigan had discussed hiding overnight in the state capitol so they could simultaneously have pro-Trump electors cast a competing set of votes, according to testimony former state GOP chairwoman Laura Cox provided to the Jan. 6 committee. Cox rejected the idea.

By then, Republican leaders knew they had lost a court case over the election and legislative leaders had told them they would not further challenge the results, according to an investigator's affidavit released Tuesday. The Trump electors met at the state Republican Party headquarters anyway to fill out the paperwork while others were kept out of the room. The Trump electors were told not to bring recording devices and were asked to surrender their cellphones to ensure no one recorded what they did, according to the affidavit.

The Trump electors then attempted to enter the state capitol to deliver their votes. They were turned away by police who said the state's electors had already arrived, according to a video posted online by the Detroit Free Press.

Later that day, Berden sent a text message to Haggard complaining that Maddock had written on Facebook about what they had done "even though we were all asked to keep silent," according to the affidavit. Haggard asked her fellow Trump elector whether she was told to keep quiet, and Berden told him they all were.

"We tried to gain access to the Capitol and we were denied," Maddock said at a news conference the next day. "We were holding our certified ballots in our hands. We also even just tried to say, 'Will you take these in?' or, 'Will you have somebody from Senate chambers come down and take them in?' We did everything we could to try to deliver our ballots to the Senate floor and they denied us that."

At the same news conference, Sheridan described the Republican electors as a "backup slate."

Maddock soon afterward was chosen as co-chairwoman of the state Republican Party. She did not seek another term this year.

A year after the Republican electors met, Maddock described what happened at an event hosted by the conservative group Stand Up Michigan. "We fought to seat the electors. The Trump campaign asked us to do that," she said, according to a recording obtained by CNN at the time.

Michigan Secretary of State Jocelyn Benson (D) said Tuesday she was pleased to see charges being brought and hoped other states would consider following suit.

"I've spent a lot of today preparing for 2024's presidential election and a lot of those preparations entail trying to anticipate a repeat of what we endured in 2020," she said. "And so today's charges really give me a lot of hope that if we do see justice for what happened in the past, that's our best strategy for ensuring — our best hope for ensuring — that they don't recur in 2024 or in any other federal election."

David Becker, the executive director of the Washington-based Center for Election Innovation and Research, said he thought criminal charges were important.

"Accountability is absolutely essential to resolving the damage done to our democracy over the last several years by election deniers and election losers," he said.

A special prosecutor in Michigan is separately investigating whether a sheriff, a former state lawmaker, attorneys and others improperly gained access to voting machines as they attempted to look into how the 2020 election was conducted. Nessel initiated that investigation but turned it over to a special prosecutor last year because one of the subjects of the probe was Matthew DePerno, who at the time was running against Nessel for attorney general.

In Arizona, Attorney General Kris Mayes (D) recently escalated her probe into the 2020 election, assigned a team of prosecutors to the case and had investigators interview many of the Trump electors and their lawyers. In Georgia, Fulton County District Attorney Fani T. Willis (D) has been conducting a wide-ranging probe of activities in her state since the release 2½ years ago of a recording of Trump asking Georgia's secretary of state to "find" votes for him. Willis has indicated that she could pursue indictments in the coming weeks.

Prosecutors in other states have remained mostly quiet and avoided offering clues about whether they are investigating the Trump electors.