Authorities in Massachusetts announced Monday they have identified the oldest unidentified homicide victim in the state dubbed the “Lady of the Dunes” whose mutilated body was discovered on a Cape Cod beach nearly five decades ago.

Ruth Marie Terry, 37, of Tennessee, was identified as the woman found on a beach in Provincetown on July 26, 1974, said FBI Boston Special Agent in Charge Joseph Bonavolonta.

Terry was identified through investigative genealogy, Bonavolonta said during a news conference, calling the development a “major break” that will “hopefully bring all of us closer to identifying the killer.”

“While we have identified Ruth as the victim of this horrific murder, it does not ease the pain for her family — nothing can,” Bonavolonta said. “But hopefully, they answer some questions while we continue to look for her killer.”

The FBI released a flyer with pictures of Terry and asked anyone with information about her killing to contact authorities.

The flyer said Terry died from a blow to the head, which likely happened weeks before her body was found. “The left side of her skull had been crushed. No weapon was found at the crime scene,” the flyer said.

Terry’s hands were missing, “presumably removed by her killer so she can not be identified through fingerprints. And her head was nearly severed from her body,” Bonavolonta…