Man walks into FBI office to confess to killing, raping woman in 1979 in Boston: DA

Susan Marcia Rose, 24, was attacked and killed on Oct. 30, 1979.

A man is in custody after he allegedly voluntarily confessed to killing and raping a young woman in Boston in 1979, according to prosecutors.

Susan Marcia Rose, a 24-year-old with red hair, was killed in an apartment building in Boston's Back Bay neighborhood on Oct. 30, 1979, the Suffolk County District Attorney's Office said Monday.

Irmer said he and the woman walked into 285 Beacon Street, which was under renovation. Irmen then allegedly picked up a hammer and fatally hit her on the head before raping her, according to prosecutors.

Irmer said he left Boston for New York the day after the murder.

A different man was arrested and went on trial for Rose's murder but was acquitted in 1981, prosecutors 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," Suffolk County District Attorney Kevin Hayden said in a statement.

Following the alleged confession, investigators took a DNA sample from Irmer and found that it matched DNA samples from the crime scene, prosecutors said.

Irmer was arraigned on murder charges Monday.