Richard Hanchett had spent years searching for his birth mother when he suddenly received a call from the FBI.

“The first thing they said to me was ‘Have you ever heard about the Lady of the Dunes?’” he recalled to Fox News Digital. “I had never heard anything about it… Ever since then, it’s been an unbelievable journey,”

In 1974, a 37-year-old woman was killed by what authorities concluded was blunt force trauma to the skull. Her mutilated body was discovered on Cape Cod, Massachusetts, a vacation hot spot. The unidentified woman became known as the “Lady of the Dunes.”

MASSACHUSETTS MAN’S DEATHBED CONFESSION RATTLES FAMILY AFTER DECADES ON THE RUN: ‘IT WASN’T A WEIRD DAD JOKE’

The case, which went cold for nearly 50 years, is the subject of a new true-crime docuseries on Oxygen, “The Lady of the Dunes: Hunting the Cape Cod Killer.” Hanchett also wrote a memoir, “Through His Eyes,” which is being published in December.

It was in October 2022 when police made a breakthrough in the decades-old investigation – the woman who was found in the dunes of Provincetown was Ruth Marie Terry of Tennessee. She was Hanchett’s biological mother.

Hanchett said that for about three weeks before he got a call from the FBI, he was having recurring nightmares about his mother.

“I kept dreaming about a man who hit a woman from behind in the head and crushed her skull,” he said. “When the police gave me the news, I put two and two together… I just felt in my heart that she saw something she wasn’t supposed to see… The nightmare just kept repeating.”

“I didn’t want to see the pictures because I knew it would be my nightmare,” he added.

Terry was struggling with financial difficulties when she gave up her son to the Hanchett family in Michigan soon after his birth in 1958. For years, he yearned to be reunited with her. In 2018, he took a DNA test, which connected him to the Terry family. Through them, he learned that she had vanished and was still missing.

FOLLOW THE FOX TRUE CRIME TEAM ON X

Terry married Guy Muldavin in 1974 – months before her remains were discovered.

“When Mr. Muldavin returned from that trip, he was driving what was believed to be Ms. Terry’s vehicle and indicated to witnesses that Ms. Terry had passed away,” Cape and Islands District Attorney Robert Galibois previously said in a statement. “Ms. Terry was never seen by her family again.”

Hanchett said that Terry’s family had their suspicions about Muldavin.

“When I first met my family, my cousin told me about this guy – I later learned he was a sick person,” said Hanchett.

According to the docuseries, Muldavin had written a book, “Cooking with Rump Oil,” which featured disturbing illustrations. One of its so-called recipes, “Cape Cod Shid,” appeared to hint at the crime. It also included a character with auburn hair, similar to Terry’s.

The book was published two years after Terry’s murder.

SIGN UP TO GET THE TRUE CRIME NEWSLETTER

Once Terry was identified by police, the focus turned to Muldavin, an antiques dealer. He was also the prime suspect in the death of another one of his wives and a stepdaughter in Seattle in the 1960s. According to newspaper reports at the time, human remains were found in the septic tank of his home. He was caught in New York City and charged with “unlawful flight.”

“Everywhere he lived, someone died,” said Hanchett.

Muldavin died in 2002. He was 78.

When Terry’s body was discovered decades ago, she was lying naked on a beach blanket with her hands severed. She was nearly decapitated. Authorities believed she was killed several weeks before her body was found.

Previously, authorities tried to identify her by exhuming her remains, performing clay model facial reconstruction, and releasing age-regression drawings of her face. She was identified using investigative genealogy, the use of DNA analysis in combination with traditional genealogy research and historical records. Investigators also learned that Terry had ties to Michigan and California, where Muldavin resided.

In 2023, authorities in Massachusetts concluded that Terry was killed by her husband. The case was closed.

GET REAL-TIME UPDATES DIRECTLY ON THE TRUE CRIME HUB

“The only question I did not get answered was the why,” Hanchett explained. “A lot of times, I feel she saw something she wasn’t supposed to see… She was at the wrong place at the wrong time. And everything I learned about Guy told me that he was not a good person. He was a criminal. He killed before my mom. This was not new to him. This was who he was.”

Hanchett said he’s speaking out today because he wanted to clear some misconceptions about his late mother, which he said continue to linger.

“It’s been said she was a hooker – she was not a hooker,” Hanchett stressed. “She was a mother, a sister and an aunt. She was a beautiful person. She didn’t deserve what happened to her. She was poor and worked hard her whole life to try to get ahead. It took me a long time to understand that she made the right decision for me. She was years ahead, stronger than I ever would’ve been at that age to do the right thing.”

“I wish I could have met her,” he quietly said. “I wanted to give her respect and dignity back.”

When asked if justice was served, Hanchett replied, “It will be.”

“What I mean by that is it could have been solved a long time ago – it should have been solved a long time ago,” he said. “That’s what bothers me. My life would’ve been completely different. It wouldn’t have changed what happened to her, but for years I didn’t know if she was still alive. My dad, uncles, aunts, grandfather – they all wondered what happened to her.”

“I am thankful that the case was able to be closed in the end, but deep down I’m upset because… this case could have been solved a long time ago. Do I feel justice was served? I never heard of someone being convicted after they died. Have you? I wish he was still alive to feel justice.”

About two weeks ago, Hanchett traveled to Provincetown to lay a stone on his mother’s grave.

“For close to 50 years, I wondered who my mom was,” he said. “It was surreal to be standing there, right by her grave. I couldn’t believe that I was finally there, with her.”