The mayor of Elmwood Park was arrested Monday after authorities say he interfered in the 2017 mayoral election.

Frank Caramagna, 74, resigned on Sunday, the Bergen County Prosecutor's Office said. Between March 2017 and November 2018, Caramagna allegedly filled in ballots of other registered voters, according to the Prosecutor's Office.

Caramagna was Elmwood Park's first Democratic mayor in nearly 50 years. He was the first person elected to the post after the death of longtime Mayor Richard Mola in October 2016. Robert Colletti served as the interim mayor after Mola's 45 years of service.

Colletti was also Caramagna's opponent in the 2017 election. It was a close election, with Caramagna receiving 2,348 votes and Colletti 2,030. The tally was even closer before mail-in, provisional and absentee votes, with Caramagna holding only a three-vote lead after Election Day. Colletti could not immediately be reached for comment.

Caramagna was released from the Bergen County Jail on Monday. He did not immediately respond to messages left for him.

Elmwood Park Borough Administrator Michael Foligno said the Borough Council will likely discuss the situation at Thursday's meeting.

"It’s a bit of a shock," Foligno said. "I've known Frank Caramagna for many years in his capacity as a council person and then as mayor. But we’ll move forward as a community and as a governing body."

Council President Daniel Golabeck was also surprised.

"He is entitled to full due process," Golabeck said in a statement. "This resignation will not slow down the council's work on the important issues we are confronting and working on nor will it affect any municipal services. The business of the borough and the council will continue unaffected."

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Former Elmwood Park Councilman Anthony Chirdo alluded to ballot tampering during his final meeting before stepping down on Aug. 16, 2018.

"Mayor, you do do an excellent job of absentee ballots," Chirdo said at the time. "You got 446 absentee ballots last year, which is outstanding, and I’m just curious: Out of those, how many did you actually personally collect?"

Chirdo's comments begin at the 37-minute mark.

Chirdo was met with a chorus of people on the council saying it was illegal to collect ballots personally, and that he was out of line.

"You never made a contribution since I’ve been mayor here," Caramagna said to Chirdo during the meeting. "Never once; always been negative. You, as an Eagle Scout — you should be ashamed of yourself, because you make a lot of accusations. Shame on you. I thought you were a better man. You better go away."

When asked Monday about his 2018 comments, Chirdo said they speak for themselves.

"There was a long history of concern about vote-by-mail ballots over the years there," he said. "Based on today, those worries seem warranted. It’s a sad day for the town."

November 2017 marked the fifth attempt by Caramagna to become mayor. The father of three and grandfather of six taught Italian and Spanish for many years at Elmwood Park High School and also served on the Board of Education.

He is on the ballot in the June primary for re-election, running against Colletti and Magdalena Giandomenico. His term expires Dec. 31.

Caramagna is scheduled to appear in court on May 22.