One of three men charged in January with illegally voting in both Rhode Island and another state in the 2020 election opted not to fight the charges, pleading no contest on Monday to two counts of mail ballot fraud in Rhode Island.

Under the plea agreement Robert E. Nickerson, 80, agrees to not contest the felony charges, but does not admit guilt. He was sentenced to three years of deferred prison time on each count and agreed to pay $500 to the state’s Crime Victim Compensation Program.

Nickerson registered to vote in the town of Portsmouth in 1996 and voted in the November 2020 general election, according to court documents. He registered to vote in Florida in March 2020, and also voted by mail there in the 2020 election.

When reached by phone, Nickerson confirmed that he had pleaded nolo contendere (no contest) to the two felony charges. He said he has lived in Portsmouth for 26 years and also lives near Fort Lauderdale, Florida, but declined to comment further.

Blake Collins, a spokesperson for the Rhode Island Attorney General’s office, said the prosecution and the sentence were appropriate, given Nickerson’s age and that he did not engage in violent conduct.

“He has been charged with a felony and held accountable for that felony conduct,” Collins said in an email, “and under the terms of the sentence imposed by the Court, for the next three years he must be of good behavior or be subject to further proceedings as a probation violator and face the prospect of incarceration.”

The fraud was initially flagged by election officials in Florida, according to prosecutors. A voter services manager in Indian River County, Florida, contacted the Portsmouth Board of Canvassers, which oversees elections, and provided documents indicating Nickerson voted by mail in Florida. Portsmouth town officials eventually confirmed Nickerson also voted by mail in Rhode Island and filed a police report.

The Indian River County elections official who initially contacted the town of Portsmouth has since retired, but the county Supervisor of Elections said Thursday that they suspected election fraud after receiving an anonymous tip via email.

“We take election fraud very seriously, when it arises, though fortunately those instances are rare,” Collins said. “At a local and state level, there exist systems that monitor voter registration and elections that identified the three cases charged by this Office.”

It is not clear, however, if this instance of double-voting would have been flagged if not for the emailed tip.

Voter fraud is extremely rare, according to experts. A comprehensive review of 2020 election results by the Associated Press, for instance, found fewer than 475 cases out of millions of ballots cast in six battleground states that swung the presidential election.

Rhode Island has charged three men with mail ballot fraud from the 2020 election, including Nickerson. More than 517,000 people voted in the general election in the state and now-President Joe Biden won the state by 107,564 votes.

Paul Krikorian is charged with two counts of mail-ballot fraud for allegedly voting by mail in Narragansett and Vero Beach, Florida. Jimmy McRoy is charged with two counts of mail-ballot fraud for allegedly voting by mail in Portsmouth and Farmerville, Illinois. Their cases were postponed until June.

This story has been updated with additional information from the Rhode Island Attorney General’s Office and the office of the Indian River County Supervisor of Elections.