At least a dozen mail ballots were stolen, fraudulently filled out and submitted in Mesa County for the Nov. 5 election in a scheme announced Thursday by Colorado Secretary of State Jena Griswold. Authorities detected the scheme before most of the ballots were processed, she said. But three were successfully cast after clearing a signature-review process. A fourth ballot nearly made it through, but it was flagged after the legitimate voter received a notification that their ballot had been cast, Griswold said. Election officials cannot retrieve the three fraudulent ballots, Griswold said, and they will be counted. All of the fraudulent ballots were completed, including with a required signature on the back of the return envelope, and submitted via U.S. Postal Service boxes, rather than ballot drop-box locations. At least some of the ballots appear to have been signed by the same person, Griswold said. She declined to say whether anyone has been arrested or if any suspects have been identified. Mesa County uses an electronic signature verification process, comparing it to signatures on file, and election judges also manually check the signatures on the back of the envelopes at times. The signature-verification system helped identify the scale of the issue in Mesa County. Two voters also reached out to election officials after they received communications to cure ballots — meaning to fix concerns with their signatures — that they hadn’t ever received. In the case of the three ballots that were accepted for counting, all were kicked out for further review by the automatic signature verification system; they were then accepted by the same election judge, said Jack Todd, a spokesman for the secretary of state’s office, after a news conference Thursday afternoon in Denver. That judge has been reassigned, Todd said. He added that secondary review by a human judge isn’t unusual. RELATED: Colorado voter guide: Stories, explainers and endorsements for the 2024 election Mesa County is home to more than 112,000 active registered voters, according to Secretary of State data. Despite three ballots making it through the system, Griswold and Matt Crane, the executive director of the Colorado County Clerks Association, said the incident was an example of the election system working to catch potential fraud. “The team at Mesa County is reexamining every ballot return envelope that has been received at this point. The investigation into the situation is ongoing,” Griswold said. “What we also know is that Colorado elections are safe and secure, and this attempt at fraud was found and investigated quickly because of the groundbreaking tools that we have here.” Griswold said another ballot issue was under investigation elsewhere in the state. Todd said later that the situation was similar to what was identified in Mesa County and that he believed a local agency was investigating. He and Griswold declined to provide any additional information. The affected ballots in Mesa County were all stolen from addresses within a close geographic proximity, Griswold told reporters. Voters who had their ballots stolen — including those three whose ballots were successfully cast and will be counted — will still be able to vote. Griswold said her office learned about the scheme Wednesday, a day after Mesa County officials identified it. She would not comment on when the ballots were believed to have been stolen, nor would she comment on whether the ballots were cast in favor of one political candidate or party or another. A criminal investigation in Mesa County is underway, Griswold said. The Mesa County District Attorney’s Office declined to comment. The U.S. Postal Service did not immediately respond to a request for comment. In a statement sent after Griswold’s press conference, Mesa County Clerk Bobbie Gross said she was “fully committed to ensuring the integrity and security of our elections” and that her office is “currently investigating attempted election fraud.” But Gross, a Republican, criticized Griswold’s decision to reveal the scheme publicly and said it was “critical that we follow proper procedures to ensure a thorough and effective investigation without tipping off those involved.” Related Articles Election | Hundreds of ballot drop boxes, voting centers open across Colorado: “The most we have ever had in any election” Election | Colorado voter guide: Stories, explainers and endorsements for the 2024 election Election | Colorado man accused of threatening to kill Democratic election officials pleads guilty Election | RTD to offer two “Zero Fare” days to encourage voter participation Election | Former Colorado county clerk Tina Peters sentenced to 9 years for voting data scheme Now serving her second term in office, Griswold, a Democrat, has frequently defended the security of Colorado’s mail-voting system, in which ballots are mailed to all active voters several weeks before the election. Griswold and Crane again sought Thursday to reassure voters, despite the fraud, that the state’s elections are safe and secure. “At the end of the day, our system is done by humans. It’s done by people who are overseeing the entire Colorado election model,” Griswold said. “Two big things: We’re going to continue to work very closely with the Mesa County clerk to ensure compliance with our electoral law, but that also the system did work.” Mesa County, home to Grand Junction, has been at the center of past concerns around elections in recent years, centered on former Clerk and Recorder Tina Peters, who helped spread rampant false claims about voting machine fraud in the 2020 election. She was convicted of criminal charges in August and sentenced to nine years in prison and jail for her role in a data breach scheme that involved other election deniers. Prosecutors said she allowed a man to access the county’s election system using someone else’s security badge and deceived other people about his identity. Staff writer Nick Coltrain contributed to this story. Stay up-to-date with Colorado Politics by signing up for our weekly newsletter, The Spot.