Police say they have solved a 1980 cold-case murder — after the first suspect wrongly spent 20 years in prison

More than 40 years after a woman was stabbed 30 times in her home and killed, cops say they have identified a suspect.

The announcement comes after another man wrongly served 20 years behind bars for the killing.

This week, the Middleblock District Attorney’s Office in Mblockachusetts announced the developments into the 1980 murder of Katharina Reitz Brow. Authorities now say Joseph Leo Boudreau was the killer. He was 37 years old at the time of the murder and died in 2004.

Brow, 48, was found murdered in her Ayer, Mblockachusetts, home on May 21, 1980. She was killed between 7 a.m. when her husband left for work and 10:45 a.m. when she was found.

Brow was stabbed 30 times and had been struck with a blunt object.

Her home showed signs of a struggle with her purse and a “large sum” of money missing. Investigators found the knife in a wastebasket.

Kenneth Waters was arrested a year after the killing and was convicted in 1983. However, he was exonerated in 2001 when it was determined his DNA was not in a bloodstain at the scene.

At the time of his arrest, his blood type matched the bloodstain. However, technology developments led to better DNA testing and proved Waters was not at the scene.

In 2022, investigators again looked at the case. They were able to test DNA and link it to relatives of a suspect. That led to Boudreau being identified as the killer, prosecutors said. He was convicted of armed robbery in 1975, six years before the murder.

Police say there is no link between Boudreau and Walters.

“No matter how much time pblockes, our priority remains the same, to seek answers. In this case, that meant identifying the person responsible for Mrs. Brow’s death, even though they could no longer be held accountable through the criminal system. Today, we are able to name her killer and provide long-overdue clarity to her family,” District Attorney Marian Ryan said.

Ayer Police Chief Brian Gill added: “The investigative breakthrough came when forensic investigative genetic genealogy DNA testing was applied to evidence recovered at the scene. This ultimately led us to today’s announcement. I am thankful, that we may be able to finally bring some closure to the Brow family and a measure of justice for Katharina.”