On the eve of Halloween in 2018, Michael Carroll’s son felt a sudden chill when his shovel clanked against what appeared to be tattered cloth and bones in their basement.

Chris Carroll and his brother, Mike Carroll Jr., had been excavating their family home in Lake Grove, Long Island, New York, for several months. Their father, who initiated the digging, had recently experienced a stroke and required assistance to navigate the stairs.

“Dad, I think I’ve found something,” Chris announced.

The story of Michael Carroll’s father, George Carroll, is now the focus of a gripping true-crime documentary titled “The Secrets We Bury,” directed by Patricia E. Gillespie.

Neither Chris nor his brother could have anticipated that they would unearth the skeletal remains of their grandfather, George Carroll, who had mysteriously vanished over 50 years earlier.

The months-long excavation is the subject of a new true-crime documentary premiering Dec. 16 on Investigation Discovery (ID), titled “The Secrets We Bury.”

Michael Carroll spent months digging through the basement floor, driven by the belief his father could be hidden below. (Courtesy of ID)

Patricia E. Gillespie, a New York-based director, came across the story of Carroll’s quest in a local newspaper. Intrigued, she began her own investigation and soon located him.

Filmmaker Patricia E. Gillespie first learned of Michael Carroll’s story in a local paper before meeting him at a Dunkin’ Donuts to discuss his father George’s disappearance. (Leon Bennett/Getty Images)

“I met Mike just a couple of days after he uncovered the mystery of his father,” Gillespie told Fox News Digital. “We really hit it off so much that at the end of the meeting, he took me down to the basement, where there was still a giant hole. I thought to myself, ‘I’m really lucky he’s a good person.’”

“For many, many years, people thought Mike and his sister Jean Kennedy were crazy,” Gillespie said. “They were just told, ‘Your dad left. Why can’t you accept this?’”

“Solving the mystery itself became a jumping-off point for a thousand other little mysteries and secrets,” Gillespie added.

People often dismissed Michael Carroll as delusional, yet he pressed on with his search. (Courtesy of ID)

George, a U.S. Army Korean War veteran, disappeared in 1963. His son, Carroll, was about 8 months old at the time. Carroll’s late mother, Dorothy Carroll, always said he went out for cigarettes and “just never came back.” Rumors claimed he met a woman in Korea and started a new life with her. The documentary noted George was never reported missing.

George Carroll is seen here with his daughter, Jean Kennedy, in a still from a family Super 8 video from the 1960s. The father of four vanished from his Long Island home in 1963. (Courtesy of ID)

“He came back from this war with a bunch of kids at home,” Gillespie said of George. “They weren’t talking about what had happened in the war. You didn’t necessarily engage with a therapist in those generations. It was just a different time. It must have been tough to go from the Korean War to your tiny little house with a bunch of kids. [But] his children loved him. For those too young, they loved the idea of him.”

A believer in the supernatural, Jean Kennedy consulted a psychic for clues about her father. (Courtesy of ID)

For decades, the Carroll children wondered what became of their father. Desperate for answers, Kennedy — a no-nonsense believer in the supernatural — consulted a psychic in 2010. She convinced her brother to join her, even though he was skeptical.

A baby photo of Jean Kennedy posing on her father’s motorcycle from the 1950s. (Courtesy of ID)

The psychic told them that George was murdered and buried in the basement. Carroll bought the property from his mother in 1993. Dorothy died of cancer in 1998.

“Jean says it’s her ‘long-distance call’ to her mom,” Gillespie said of Kennedy’s interest in mediums. “Like all of us, when you lose somebody you care about, there are all these conversations you wish you could have had or things you wish you could have worked out. And for Jean, I think the psychic was an opportunity to do that — to make that long-distance call to the great beyond.”

The Carroll children are seen here with their mother, Dorothy Carroll. (Courtesy of ID)

According to the documentary, George’s brother had also told Carroll that his side of the family believed George was killed.

Michael Carroll was just 8 months old when his father vanished. (Courtesy of ID)

Carroll, desperate for answers, began digging. He never wanted to believe George had abandoned him and his three older siblings. Even after uncovering a dark family secret, the mystery wasn’t over.

Chris Carroll examines clothing fibers uncovered in the hole he dug in the basement. (Courtesy of ID)

“It opened up a door to something so much deeper,” Gillespie said. “You’re looking for a man, you find him in these dramatic circumstances — the end, right? I think a lot of stories end there. But for them, it was just the beginning of figuring out how to reconcile with this. And that answer wasn’t found in forensics, a police report or a court proceeding.”

After Michael Carroll suffered a stroke, his sons took over digging in the basement. (Courtesy of ID)

When police initially received a call from Carroll, they laughed it off, believing it was a prank. But Carroll was persistent, and they eventually stopped by the home. To their dismay, there were bones several feet below the basement. They were later confirmed to be George’s.

Police classified George’s death as a homicide. His skull had been fractured by blunt-force trauma.

Michael Carroll’s family home in Lake Grove, Long Island. (Fox News)

Carroll believed the person who may have been responsible for his father’s disappearance was his stepfather, Richard Darress. He was a young handyman George had hired to help with a construction project and who later lived in the home.

Dorothy Carroll and Richard Darress are seen here in the 1960s.  (Courtesy of ID)

Soon after Dorothy told her children their father had abandoned them, she married Darress. They shared a son, “Richie,” before divorcing in 1983. According to the documentary, the Carroll siblings claimed their stepfather was physically abusive and had sexually assaulted the girls.

“Richie [who appeared in the film] was put in such a tough position,” Gillespie said. 

A family photo of Dorothy Carroll and her second husband, Richard Darress, from the 1960s. Darress was a live-in handyman before George Carroll disappeared. (Courtesy of ID)

“No matter who your dad is, you love your dad. You don’t want to believe anything tough about your dad. But some of the other kids started to talk — not so much about George Carroll, but about some of their own negative experiences growing up with their stepfather. I think a lot of guys in Richie’s position would just plug their ears and say, ‘No, not my dad. Not part of me. Not my name.’”

Rich Darress struggled to hear the claims and theories that were being made about his late father. (Courtesy of ID)

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“Richie didn’t,” Gillespie continued. “Richie believed his siblings. He said to us, ‘My siblings are my real family. So, of course, I believe them.’ I think that he just showed so much strength and care. … He really prioritized his siblings’ feelings. At the same time, the siblings were also working to protect him because, as they pushed deeper into this mystery, they started to find creepier, scarier things — more disturbing stuff. But they always thought, ‘What about Richie? How is he going to feel?’”

Michael Carroll is seen here with his mother’s piano.  (Courtesy of ID)

Darress died in June 2018 at age 77, a funeral home in Laredo, Texas, previously told Fox News Digital. Before his death, he had been living in Mexico, across the border from Laredo.

Richard Darress and his son, Rich, posing together at the beach in a photo from the 1970s. (Courtesy of ID)

For years, the siblings tried to question their mother, hoping she had clues that could lead to answers. But Dorothy would curtly remark that George wasn’t “a good guy.” While there’s speculation she may have been involved in George’s disappearance after their tumultuous marriage, her children continue to defend her.

“When that initial wave of press came out after Mike found his dad, a lot of it pointed the finger very firmly at her,” Gillespie said. “Yet the thing that stood out to me the most about their relationship with their mother is how all of them love her. All of them absolutely worship her.”

Michael Carroll will never truly know what happened to his father. (Courtesy of ID)

“There was some really complicated stuff that went on within the family,” she said. “There were some unanswered questions that, frankly, will remain unanswered forever, because most of the people had died by the time George was found. But what struck me most was their unyielding defense of their mother. They are united by their love for her to this day.”

Patricia E. Gillespie told Fox News Digital that the Carroll children remain fiercely protective of their late mother, Dorothy Carroll. (Courtesy of ID)

On Oct. 25, 2019, George was laid to rest with military honors at a national cemetery on Long Island. Police said they may never determine how he died.

“About two weeks ago, Mike’s son sent me a picture,” Gillespie said. “They finally filled in the hole in the basement. There’s a feeling that you can finally grieve, that you’ve done what you needed to do for your family — both the ones who are here and the ones who are gone. … This story goes beyond just the mystery of how this man disappeared.”