Michigan Attorney General Dana Nessel, pictured speaking at the Democratic National Convention in August, filed charges against seven people for double voting in the state's primary election. Chip Somodevilla/Getty Images

Seven people were charged with felonies in Michigan for allegedly double voting during August's primary election, according to the Michigan attorney general's office.

Four of the people voted in person at their St. Clair Shores polling station and through absentee ballots, while three municipal assistant clerks knowingly allowed their votes to be counted twice, Attorney General Dana Nessel said in a statement on Friday.

Officials did not reveal the political party of the voters or the clerks, nor the party of the candidates the voters selected.

Her office said the four — Frank Prezzato, 68, Stacy Kramer, 56, Douglas Kempkins, Jr., 44, and Geneva O'Day, 62 — appeared in person at the polling station requesting ballots for the Aug. 6 primary. They were told by election workers that their absentee ballots had already been received, according to Nessel.

Despite the existence of the ballots' paper trail, three assistant clerks — Patricia Guciardo, 73, Emily McClintock, 42, and Molly Brasure, 31 — allowed the four to vote in person by illegally alerting "the State Qualified Voter File" to show that the received ballots had been rejected even though they had already been counted, Nessel said.

The three clerks then told the election workers to override the system and give the four in-person ballots.

"The voters cast these ballots, which were then counted alongside their absentee ballots, resulting in double votes," the AG's office said in the statement.

"There are procedures in place to ensure that this does not happen, and that's why it so rarely does," Nessel said during a press conference in Detroit, the Detroit News reported.

"It really took a perfect storm to come together to allow these four individuals to double vote, which included voters who were willing to vote twice ... poll workers who did not turn them away as they should have and municipal clerks who illegally altered the qualified voting file," she said.

Michigan is a critical battleground state in this year's presidential election between Donald Trump and Vice President Kamala Harris.

The Detroit News reported that Macomb County Clerk Tony Forlini's office on Aug. 15 informed county prosecutor Pete Lucido of "possible double voting involving four individuals."

Lucido, a Republican, announced on Aug. 29 that he wouldn't file charges.

Lucido claimed that the report submitted by local police indicated that there was "no malicious or criminal intent displayed by any of the voters, each claiming an honest mistake" because of potentially spoiled absentee ballots.

"The people did everything in their power to make sure that they only voted once," Lucido said at the time, the newspaper reported. "The intent is critical on our part on whether we charge."

Nessel, a Democrat, said her office believed Lucido "had conducted no additional investigation" beyond the efforts of local police.

She called Lucido's handling of the probe "insufficient."

Lucido, who is running for re-election, said he respects Nessel's "jurisdiction and investigatory resources."

"It is not unusual for the Attorney General to charge criminal cases in which a local prosecutor did not," he said, the Detroit News reported. "I expect justice will be served. I have no further comment on this ongoing case."