WATCH: Murder Suspect in Claire Gravel’s Killing Being Indicted, DA Says

A suspect has been indicted for murder in the killing of a 20-year-old woman whose body was found by the side of Massachusetts Route 128 in Beverly in 1986, prosecutors announced Wednesday.

An Essex County Grand Jury has indicted John Carey, 63, for murder in connection with the strangulation death of Claire Gravel, according to Essex District Attorney Jonathan Blodgett. Carey is currently in prison, serving a sentence at MCI Concord for a 2008 conviction of attempted murder, Blodgett said.

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Prosecutors said during the announcement Wednesday that investigators have interviewed dozens of witnesses and persons of interest over the years, following leads and tips.

"A new lead developed in 2012," Blodgett said. "Assistant district attorneys, state police detectives assigned to the Essex DA's office and Salem and Beverly police worked diligently to bring about the result we have today. Evidence recovered from Claire's clothing was instrumental in solving this case."

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Gravel's killing had been unsolved for more than 35 years.

Gravel, a Salem State College sophomore from North Andover, was last seen at Major Magleashes' pub in Salem on June 29, 1986, according to an article in The Daily News written on the 30th anniversary of her death. Prosecutors believed she was strangled, but a motive was never identified.

"We continuously review cold cases, hoping that new techniques and a fresh look will result in a breakthrough," the district attorney said. "We are mindful of the victims, and their family members who continue to want answers. They are not forgotten."