The Justice Department warned states Wednesday against violating the Civil Rights Act when conducting post-election audits.

The memo was issued as Arizona is conducting a controversial review of 2.1 million ballots cast in the 2020 presidential election in Maricopa County. The audit, ordered by the state’s Republican-led Senate, is being led by Cyber Ninjas, a small Florida cybersecurity firm whose CEO has promoted baseless conspiracy theories that widespread election fraud cost Donald Trump reelection.

Some lawmakers in other states that Trump lost have pushed for similar audits.

“Election audits are exceedingly rare,” the Justice Department guidance says. “But the Department is concerned that some jurisdictions conducting them may be using, or proposing to use, procedures that risk violating the Civil Rights Act.”

The DOJ says it wants to ensure that federal election materials are being retained for 22 months, as required by law, and that auditors are not intimidating voters.

“[W]here elections records are no longer under the control of elections officials, this can lead to a significant risk of the records being lost, stolen, altered, compromised, or destroyed,” the memo says. “This risk is exacerbated if the election records are given to private actors who have neither experience nor expertise in handling such records and who are unfamiliar with the obligations imposed by federal law.”

Those found to be in violation of preserving election materials could face fines of up to $1,000 and one year in prison for each infraction.

Earlier this month, Maricopa County’s Board of Supervisors voted to spend nearly $3 million to replace its voting machines, saying they were compromised because they were in the custody of firms not accredited to handle election equipment.

The Justice Department also warned about the potential problems that could have been caused by a since-abandoned plan by Cyber Ninjas to knock on doors of some voters to verify they lived at their stated addresses. 

“This sort of activity raises concerns regarding potential intimidation of voters,” the document says. “For example, when such investigative efforts are directed, or are perceived to be directed, at minority voters or minority communities, they can have a significant intimidating effect on qualified voters that can deter them from seeking to vote in the future.”

In a call with reporters Wednesday, a DOJ official said the memo “sets down a marker that says the Justice Department is concerned about this and we will be following this closely.”

When asked if the DOJ might take action in response to any audit, the official said they could not comment on any investigations that might be ongoing.

Wednesday’s warning was not the first issued by the Justice Department on the matter. In May, it sent a letter to Arizona Senate President Karen Fann outlining the same concerns about preservation of materials and voter intimidation.