GARDINER — Local officials across the state are warning they have received scattered reports of strangers offering to return absentee ballots for voters, which is an illegal practice.

Officials say the incidents can result in those ballots not being received and counted.

Absentee ballots are required to be returned by the voter, an immediate family member or a third party who was designated to handle the ballot when it was requested. But in Gardiner, Bangor and Van Buren, local election officials have reported that undesignated individuals have offered to return some residents’ ballots to a drop-off location.

The primary concern with the alleged “ballot harvesting” — offering to return ballots for others — is that the ballots may not be returned at all, Secretary of State Shenna Bellows said. Ballots that have been obviously tampered with will be investigated, Bellows said, but reports of missing ballots are more difficult to look into.

Gardiner City Clerk Kathleen Cutler helps a resident sign up for an absentee primary ballot on Feb. 1. at Gardiner City Hall. Joe Phelan/Kennebec Journal file

Gardiner City Clerk Kathleen Cutler said the city has received two separate reports recently of a person driving a car with Massachusetts license plates offering to take absentee ballots and deliver them. Cutler could not confirm any details about the identity of the person, but said the two residents reported the individual used similar language.

“The City Clerk’s office has been made aware of people knocking on doors offering to return absentee ballots,” Gardiner officials said in a statement Monday morning, following the second complaint of potential ballot harvesting. “Please be aware that giving your ballot to a stranger may result in your ballot not being counted.”

Maine state law allows a “third person” to deliver a ballot back to the municipal clerk only within two business days of the ballot being issued to that third person. Clerks can only issue absentee ballots to family members or a third person if the ballot was requested in-person or via mail — not if it was requested by phone or electronically. Most states allow a previously designated non-family member to return ballots.

But organized, undesignated ballot harvesting is illegal in Maine, Bellows said. A person who “delivers, receives, accepts, notarizes or witnesses an absentee ballot for any compensation” is guilty of a Class D crime under state law, punishable by up to a year in prison and a $2,000 fine.

Cutler said Gardiner rarely receives requests for a designated third person to deliver and return ballots in the first place, and had never received complaints about ballot harvesting in her 17 years working there. Almost always, she said, the voter or an immediate family member returns the ballot. If an undesignated person tries to return an absentee ballot the city will challenge the ballot, she said — because a strict chain of command for each ballot helps maintain trust in the process.

“It doesn’t mean that their vote won’t count; it’s just that’s not the way the process works,” she said. “We can’t have people, willy-nilly, picking up ballots for people, because then it challenges the integrity of the ballot itself.”

In Bangor, officials said last week in a statement they were “aware of at least one individual knocking on doors offering to return absentee ballots for residents.” Officials reported the incident to the Maine Department of the Secretary of State for investigation, which determined canvassers affiliated with a group called Patriot Grassroots were knocking on doors and offering to return ballots.

Bellows said Patriot Grassroots — an organization dedicated to forming “an army of conservative, cause-driven patriots capable of running the most effective grassroots campaigns in the world” — apologized and told canvassers to stop offering to take ballots to drop-off locations after the secretary of state’s office delivered a cease and desist letter on Thursday. Bellows said the reports were the first instance of ballot harvesting during her tenure as secretary of state.

“We understood from their organization that they had deployed canvassers in a number of places,” Bellows said. “Fortunately, most Mainers have very good common sense and knew that something wasn’t quite right.”

It was unclear whether the reported incidents in Gardiner were related to Patriot Grassroots, Bellows said, but the secretary of state’s office was investigating the claims.