Jason Freeman, who says he is the grandson of notorious cult leader Charles Manson, wants to set the record straight in a new two-hour documentary.

On April 13, Reelz is premiering “Charles Manson: The Funeral,” which explores how the Bradenton, Fla., resident fought to win custody over the corpse of one of the most infamous murderers of America.

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Manson was convicted of organizing the horrific slayings of Hollywood actress Sharon Tate and six others in 1969 — killings so shocking they continue to resonate nearly half a century later.

Sharon Tate was expecting her first child at the time of her death. (Getty)

At the time of her death at age 26, Tate, who was married to filmmaker Roman Polanski, was pregnant with the couple’s child.

The 50th anniversary of the Manson murders is on Aug. 9, which has sparked several films including “The Haunting of Sharon Tate” with Hilary Duff; “Charlie Says” with Matt Smith – of “Doctor Who” fame – as Manson; “Once Upon a Time in Hollywood” directed by Quentin Tarantino and starring Brad Pitt and Leonardo DiCaprio; and “Tate,” starring Kate Bosworth as the ’60s starlet, which has no set release date at the moment.

Manson was originally given the death penalty but it was ruled unconstitutional in California in 1972. His sentence was changed to nine consecutive life terms and he was denied parole 12 times.

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Manson died in 2017 at age 83. While the failed musician-turned-vile criminal was worshipped by the Manson 'family,' a group of ragtag followers who acted upon his every wish and whim, the only actual family member Manson had at the time of his death was his alleged grandson, who held a funeral for him once the court awarded him the body after a long legal battle involving two others.

“I wanted to film my life journey and share the story through my eyes,” Freeman told Fox News on why he participated in the Reelz documentary. “I knew at the time my grandfather was sick. … [but] I had no clue this film would ultimately chronicle his death.”

Freeman’s father was reportedly Charles Manson Jr., one of the sinister patriarch’s three known children, who later changed his name to Jay White. White was born to Manson’s first wife, Rosalie Willis. Unable to cope with the grisly murders committed by the Manson family, as well as the burden and impact of his infamous father, White killed himself in 1993.

Freeman grew up in Ohio with his mother and said he knew at an early age his grandfather was Manson. However, Freeman claimed only later he fully understood the nature of Manson’s crimes.

Jason Freeman is participating in a Reelz documentary detailing his reported connection to Charles Manson. — Reelz

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“It really hit me during history class in junior high,” he claimed. “I came in and the name Charles Manson was written on the chalkboard. When that story was opened up and revealed to me about the murders, that’s the first time I would say that I was exposed to everything. Before then… I really didn’t have the graphic details of what happened or how many people were killed.”

Freeman said that before he went public with his claim in 2012, his family avoided bringing up the name Manson in the household.

“It was always known that it was something that our family didn’t talk about,” he explained. “Back then it was harder to get questions answered…. Anytime Charles Manson’s name was brought up, it was always an issue. We didn’t talk about it much.”

Jason Freeman with his wife at Charles Manson's funeral. — Reelz

According to the documentary, Freeman began corresponding with Manson through letters and phone calls in 2011. At the time, Freeman said he wrote a book titled “Knocking Out the Devil,” which discussed his upbringing.

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“He said some friends reach out to me first,” alleged Freeman. “He read my book…. He first told me, ‘So you think you can knock the devil out of me?’ Then he starts laughing.”

But when asked what his conversations were like, Freeman shot back, “I don’t want to get into that right now.” After pressed on why he was willing to speak with Manson, he responded, “Well, because there was no one else there. And he’s family. That’s why.”

Charles Manson died on November 19, 2017. (Reelz)

In 2018, Newsweek reported at least three people claimed they had a legal right to Manson’s body, including another man claiming to be his long-lost son, as well as a prison pen pal named Michael Channels. However, a Bakersfield, Calif., county court commissioner ruled that Freeman is determined to be the surviving competent adult next of kin. Kern County commissioner Alisa R. Knight added that “no sufficient probative evidence was provided to this court to refute Freeman’s claims.”

“You have to look at the evidence they have to make the claim,” said Freeman. “It was a journey of paperwork, but it’s God’s will on how this plays out, not mine.”

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The Los Angeles Times also reported that Freeman told a judge he would not agree to a DNA test to determine the validity of his claim unless ordered to do so by the court. The test was sought out by Channels, who claimed Manson left everything to him. But Freeman maintained that a 2002 will Channels alleged he possessed is a forgery. Freeman said he would take the test if the judge orders it because he is convinced of his bloodline.

Charles Manson's funeral was chronicled in a new Reelz documentary. (Reelz)

“As we went through each court hearing, the evidence of where my father and I are bonded together legally through our paperwork, [like] social security when he passed,” said Freeman. “I gave all of my paperwork to my attorney when this started… My mother found original documents for child support and death benefits. That’s what I stood on. I stood on the relationship I had with my father, Charles Manson Jr. That’s what I’ve known all my life. If that’s good enough for the court system — if they wanted me to, they would have had me do it.”

Manson’s funeral was filmed for the Reelz documentary before his ashes were scattered in California. Freeman said he wanted to give his grandfather, regardless of his notoriety, a proper send-off. He hopes the documentary will finally set the record straight about his unusual upbringing so that he can finally move on with his life.

“If you have a belief in our God… you know we walk through this life and try to do the right thing,” he explained. “And it was the right thing for me to take that next step in my life and accepting my grandfather into my life. This is my story. And it was an experience that I would never give up. I found answers about my family that I needed to know personally. And you only have one family. There’s no one else there. It was a no-brainer for me. That’s just what you do.”

Charles Manson is a name that continues to haunt America. (Los Angeles Times/Polaris) — Courtesy of Reelz)

"Charles Manson: The Funeral" airs April 13 at 8 p.m. on Reelz. The Associated Press contributed to this report.