INDUSTRY, Maine — A local man was arrested Wednesday by the Maine State Police and charged with murder in the death of a woman whose body was found 31 years ago in Anson.

Jay S. Mercier, 55, was named in a secret indictment earlier this month by the Somerset County grand jury. He was arrested at his home at 5 Butterfield Lane in Industry without incident about 8:30 a.m., according to Stephen McCausland, spokesman for the Maine Department of Public Safety.

Rita St. Peter, 20, was found dead off Campground Road in Anson on July 5, 1980. She had last been seen walking in the early morning of July 5 crossing the bridge from Madison to Anson. Earlier in the evening she was seen drinking at a bar in Madison. At the time of her death, she was staying with friends in Anson and worked at Ken’s Family Drive-In, a restaurant in Skowhegan, McCausland said in a statement.

“This is the oldest cold case to date that we’ve been able to solve,” said Lt. Christopher Coleman of the Maine State Police.

Police said they had suspects in the case early on, but never released much information to the public, including autopsy information, according to Bangor Daily News reports from 1980.

Although state police would not release a cause of death for St. Peter, a report in the BDN on Feb. 10, 1990, said she reportedly had a fractured skull, had been beaten severely and was run over by a vehicle. McCausland would neither confirm nor deny that report.

A BDN report from July 30, 1980, cited then-Deputy Attorney General Pasquale Perrino as saying that there were similarities between St. Peter’s death and other unsolved homicides, including the death of a 24-year-old schoolteacher from Philadelphia whose skeleton was found near Old County Road in Newport in 1977.

Mercier is not a suspect in any other unsolved murders in Maine, McCausland said in a telephone interview.

As in all unsolved homicides that state police investigate, the St. Peter case remained active as detectives assigned to it reviewed the files and followed up on hundreds of leads, McCausland said.

He said the case was advanced by a recent review of all the evidence at the state police crime lab using forensic technology. State police detectives worked closely with analysts at the lab, prosecutors at the Maine Attorney General’s Office and the state medical examiner’s office.

“This unsolved homicide was worked on continuously, even outside the headlines,” said McCausland, noting that the previous record for state police cracking a cold-case homicide in Maine was 23 years. “This is a success story and there will be others.”

The case against Mercier was presented to the Somerset County grand jury, which handed up the indictment on Sept. 16. He has no criminal history in Maine, according to the Maine State Bureau of Identification.

Mercier was taken into custody by state police Detectives Bryant Jacques and Adam Kelley and transported to the Somerset County Jail in Madison. He is expected to make his first appearance in Somerset County Superior Court on Tuesday.

Mercier is divorced and was living with a girlfriend at the time of his arrest, McCausland said. The suspect has been employed as a laborer for most of his life.

St. Peter was survived by a daughter, who was 3 at the time of her mother’s death, and a half-sister. They have asked not to be contacted, according to McCausland.