Hundreds of illegal voters participated in the 2016 general election in North Carolina, according to a new report.

The post-election audit report, released by the North Carolina State Board of Elections (NCSBE), an independent and bipartisan agency that oversees elections in the state, found hundreds of illegal votes, including votes cast by felons and non-citizens, double voting, voter impersonation, and irregularities that affected mail-in absentee ballots.

The audit uncovered 441 cases where suspected active felons voted during the 2016 elections.

"In late January 2017, NCSBE sent letters to suspected felon voters identified through data audits, notifying recipients that they may have illegally voted and their registrations would be canceled in 30 days unless they objected in writing and presented evidence that they are not active felons," the report states.

"Currently, 441 files of suspected felon voters remain open after an initial screening and contacts or attempted contacts with the voters."

Investigators have referred 16 "substantiated cases" of felon voting to district attorneys to date. The remaining 425 cases are expected to be referred when the investigation is complete.

A separate investigation using state and federal databases identified non-citizens suspected of voting in the election. The NCSBE said 41 voters acknowledged they were not U.S. citizens after receiving a letter from the board of elections. The non-citizen voters came from 28 different countries.

An additional 61 voters did not respond to NCSBE's letter. Investigations into these cases are ongoing.

"A number of non-citizens said they were not aware that they were prohibited from voting," the report states. "Interviews and evidence show that some non-citizens were misinformed about the law by individuals conducting voter registration drives or, in at least one document case, by a local precinct official."

The state board of elections also is investigating 24 substantiated cases of double voting during the 2016 election.

"Some violators appear to be ‘testers' trying to find holes in the system," the audit says. "Others claim property ownership in multiple jurisdictions should allow them to vote in each, and others brush past the law to support their candidate by any means necessary. Additionally, a case that initially appears to be a double voter—an individual who votes twice—may actually be a case of voter impersonation—an individual who casts a ballot using the identity of another person."

The board said that detecting double voting and voter impersonation is a time-sensitive process. The initial review indicated there were possibly several dozen additional cases of double voting.

"While no audit exists to catch all possible cases of voter impersonation, double voter or deceased voter audits may detect such cases," the report says.

The NCSBE is continuing its investigation of voting irregularities in the 2016 elections and will refer the cases to prosecutors where necessary.

Logan Churchwell, spokesman for the Public Interest Legal Foundation, an Indiana-based group that litigates to protect election integrity, told the Washington Free Beacon the audit is a step in the right direction toward finding weaknesses in North Carolina's election system.

"This audit is a positive step in identifying weaknesses in the local election system. The State needs to be doing a better job tracking felon voters and freezing their records until sentences are complete," Churchwell said.

Churchwell added the state should implement requirements to prevent voter impersonation.

"NC would also do well to implement voter identification requirements into the absentee voting system—addressing the impersonation of dead voters and others," Churchwell said. "The continued trend of noncitizen voting can only be fixed with proof of citizenship built into voter registration applications. Simply inquiring about eligibility is not going to cut it any more."