An Oregon man has allegedly confessed to using a hammer to kill a 24-year-old woman whom he met at a Boston skating rink more than four decades ago.

John Michael Irmer, 69, was charged in the “brutal” 1979 cold case killing of Susan Marcia Rose, prosecutors for the Suffolk County District Attorney’s Office announced on Monday.

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Irmer strolled into a Portland FBI field office in August and allegedly admitted to Rose’s murder. He told FBI agents that he’d “met a woman with red hair at a skating rink around Halloween in Boston in 1979,” according to a press release issued by prosecutors. 

Irmer allegedly disclosed to investigators that the pair later walked to a property along Boston’s Charles River. Shortly after entering the home, which was under construction, Irmer told investigators he picked up a hammer and struck Rose in the head with it. The 69-year-old confessed to later raping the unresponsive woman. Irmer claimed to have fled to New York the following day.  

An autopsy later determined that Rose, whose body was found on October 30, 1979, had died from multiple blunt injuries to the head, as well as fractures of the skull and brain lacerations. At the time, Rose had been living on Dartmouth St. in Boston. She had moved to Massachusetts from Johnstown, Pennsylvania, officials said. 

In 1981, a separate man was arrested and charged for Rose’s homicide, however, he was ultimately acquitted of the crime. Since then, Rose’s murder had baffled authorities. 

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During his recent confession, law enforcement obtained a DNA sample from Irmer, which later matched DNA samples found at the scene of Rose’s killing, prosecutors said.  

Irmer was since extradited from Portland to Boston to face charges in the long unsolved slaying. He was arraigned in court on murder and aggravated rape charges in Boston Municipal Court Central Division on Monday.

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Suffolk County District Attorney Kevin Hayden described Rose’s decades-old murder as “ice-blooded.”

“Nearly 44 years after losing her at such a young age, the family and friends of Susan Marcia Rose will finally have some answers,” Hayden said. “This was a brutal, ice-blooded murder made worse by the fact that a person was charged and tried — and fortunately, found not guilty — while the real murderer remained silent until now. No matter how cold cases get resolved, it’s always the answers that are important for those who have lived with grief and loss and so many agonizing questions.”

Officials haven’t released additional information regarding the cold case investigation. Irmer is being held without bail, per a judge’s order following Monday’s court ruling, according to Boston television station WCVB-TV. It’s unclear if he’s obtained a lawyer to comment on his behalf.