Police claim they've solved 1980 cold case murder after first suspect wrongly spent 20 years in prison

Police believe they have finally found the killer of a woman who was stabbed 30 times in her home in 1980.

45 years ago, Katharina Reitz Brow was brutally slain in her home in Ayre, Massachusetts, at the age of 48.

In the years that followed her untimely death, Kenneth Waters was arrested and convicted of Brow's murder as a bloodstain at the scene of the crime matched his blood type.

But Waters went on to be exonerated in 2001 after it was found that his DNA did not match the bloodstain in question. He had been behind bars for almost 18 years.

Tragically, just six months after being freed, Waters died in an accident.

In light of all charges being dropped against Waters' in 2001, police were left without a suspect for Brow's murder — until now.

Katharina Ritz Brow was murdered in 1980 (Middlesex District Attorney’s Office)

In an announcement shared on Thursday (June 14), the Middlesex District Attorney’s Office said that it had found who was responsible for Brow's death and named Joseph Leo Boudreau as the killer. He was identified through DNA evidence.

He was 37 years old at the time of Brow's murder. She was stabbed 30 times, five of which penetrated her heart.

Boudreau was convicted of armed robbery in New Hampshire in 1975 before he murdered Brow.

In 1987 he moved to Maine, where he lived until his death at age 61.

Addressing the huge development in the decades-old cold case, District Attorney Ryan said: "Today’s announcement illustrates the cornerstones that define this Office: integrity in our convictions, persistence and an unwavering commitment to accountability. Although the original conviction in this case was vacated, we did not stop there. We do not forget when someone enters Middlesex County and violently takes a person’s life."

Investigators used DNA evidence to pin the crime on Joseph Leo Boudreau (Getty Stock)

"No matter how much time passes, our priority remains the same, to seek answers," his statement went on. "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."

Elsewhere, Ayer Police Chief Brian Gill said that Brow's murder 'shook the Town of Ayer to its core'.

"Since the conviction in this case was vacated in 2001, many investigators had been assigned to review the investigation, follow up on leads, and apply known investigative techniques," Gill's statement continued.

"Unfortunately, information to further the investigation never developed. 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."