District Attorney Andrew S. Robinson in the courtroom at Androscoggin County Superior Court in Auburn. Daryn Slover/Sun Journal 2015 file photo

LEWISTON — The chief prosecutor for Androscoggin, Franklin and Oxford counties has decided he will not seek reelection later this year.

Andrew S. Robinson, whose second four-year term as district attorney for the tri-county area ends in December, said Wednesday he is “very excited about the future.”

Robinson, 51, a Democrat who lives in Farmington with his wife and three children, has been a prosecutor in central Maine since 1999.

“I’ve reached a point in my professional life where I feel like I have done all of the amazing things that I wanted to accomplish as a district attorney,” he said. “I have had a rich and full experience, and now I’m ready for new challenges and looking for my next adventure.”

Robinson was hired under a federal grant as a domestic violence prosecutor for the district attorney’s office in Lewiston because of work he had been doing with a local domestic violence advocacy group in Farmington, helping as a volunteer to secure protection from abuse orders for women in peril.

That position eventually led to a job as an assistant district attorney.

In 2012, then-District Attorney Norm Croteau promoted Robinson to deputy district attorney.

When Croteau retired in 2014, Robinson was elected district attorney.

During his tenure, Robinson oversaw the relocation of the district attorney’s office and staff from the Androscoggin County Courthouse in Auburn to a former bank building in Lewiston next to the 8th District Courthouse.

The building is where all criminal court cases would initiate under a new criminal court process implemented statewide under the Maine Judicial Branch.

While personally handling hundreds of criminal prosecutions, Robinson has supervised a staff of 14 assistant district attorneys who prosecute a range of criminal cases referred by law enforcement agencies and officials. He also supervises 23 members of the support staff.

Robinson has modernized the manner in which prosecutors distribute materials discovery by using a secure cloud distribution.

“We’ve enhanced our use our case management system to improve the way we collect data and maintain our cases,” he said.

Robinson also has argued cases before the Maine Supreme Judicial Court, which hears appeals from lower courts.

As one of eight district attorneys in Maine, Robinson has helped draft legislation, testified before the Maine Legislature and met with governors.

Robinson has been working with the Maine Prosecutors Association and the Criminal Law Advisory Committee. He is a member of the Advisory Committee on Rules of Professional Conduct that reports to the Maine Supreme Judicial Court.

He keeps busy when not serving his official capacity as prosecutor.

Robinson teaches law classes at the University of Maine at Farmington, is president of Western Maine Community Action and is treasurer for the Farmington Public Library. He is also a board member for the Maine State Society for the Protection of Animals and serves on the board for Western Maine Addiction Recovery Initiative.

Among his more obscure accomplishments, Robinson earned an acting credit playing himself in a documentary, “Knee Deep,” about a shooting in Farmington that took place on a family farm in which the son was charged with assaulting his mother who tried to sell the farm.

As of Wednesday, the only candidate to have filed papers with the Department of the Secretary of State’s Office for Maine for Prosecutorial District 3 was Neil McLean Jr., 53, of Turner, who works as an assistant district attorney in that office. He is enrolled as a Republican.

The state primary election is scheduled for June 14.