It was a story that horrified Long Islanders and later inspired horror films. On Nov. 13, 1974, six members of the DeFeo family were murdered inside their Amityville home.

Ronald DeFeo Sr., 43, his wife, Louise, 42, their two daughters, Dawn, 18, and Allison, 13, and two of their sons, Mark, 11, and John, 9, were found dead inside their beds, each with a single bullet in their back.

They had apparently been killed in their sleep, and the family's sole survivor, the DeFeo's 23-year-old son, Ronald DeFeo Jr., would eventually confess to the murders. He was serving six concurrent sentences of 25-years-to-life in an upstate New York prison until his death on March 12, 2021.

Here's how the case unfolded.

Police respond to 112 Ocean Ave. in Amityville

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Shortly after 6 p.m. on Wednesday, Nov. 13, 1974, Suffolk County Police are called to 112 Ocean Ave. in Amityville, the DeFeo's waterfront home.

"They could have been sleeping except for the holes in their back."

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When police arrived, they found six dead bodies -- Ronald DeFeo Sr., 43, his wife, Louise, 42; their sons Mark 11, and John, 9; and their daughters Dawn, 18, and Allison, 13 -- in four different bedrooms. "They all lay there peaceful, all on their faces, all in their nightclothes, all in their beds," one police officer at the scene told Newsday. "They could have been sleeping except for the holes in their back."

There were no signs of any struggles

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The Suffolk County Medical Examiner determined that each of the victims died from wounds caused by .35-caliber bullets. Judging from the condition of the bodies, police said, they believed the victims were all shot sometime between 5:45 a.m. and 9 a.m. on Nov. 13, 1974, and there were no signs of any struggles. Officers and workers from the Suffolk County Medical Examiner's office are seen bringing one of the bodies out of the DeFeo home.

DeFeo reported the murders

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On the night of the murders, Ronald DeFeo Jr. came rushing into Henry's Bar, which was located on Merrick Road, about a half-mile from his house, and told his friends that he came home to find his parents dead. DeFeo originally told police that when he arrived at the house, the door was locked so he crawled through an open window, discovered the grisly scene and then ran to get help. Upon returning to the house with DeFeo, one of his friends called 911.

"They seemed like an average good family."

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The DeFeos were considered devout Catholics. The family regularly attended services at St. Martin of Tours in Amityville. The three youngest children were also students in the parish's elementary school and Dawn had just graduated from St. John the Baptist High School in West Islip. "They seemed like an average good family," the Rev. James McNamara, then an assistant pastor at the family's church, told reporters. McNamara went to the house after the murders to administer last rites.

Neighbors heard barking

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The DeFeos owned two dogs -- a German shepherd and a sheepdog named Shaggy (pictured above) -- and about 3 o'clock on the morning of the murders neighbors told police they had been awakened by the dogs, who had been barking for about 20 minutes. Ronald DeFeo Jr. later confessed to police that he murdered his family around 3:30 a.m.

"Then I shot my brother"

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Det. George Harrison, who signed the complaint accusing Ronald DeFeo Jr. of the murders, said that during interrogation DeFeo calmly acted out the murders for detectives, and said: "I took the rifle and ammunition from my room, then I shot my brother Mark like this."

The search for the murder weapon

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In a photo dated Nov. 14, 1974, Suffolk County Police Sgt. Earl Eaton checks the DeFeo's pool for the murder weapon. He found nothing, but a .35-caliber Marlin rifle was found the following day in Amityville Creek, near the DeFeo home, and ballistics tests confirmed that it was the murder weapon.

Murder indictment follows funeral

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On the same day that the six slain DeFeo family members were laid to rest, a Suffolk County grand jury indicted Ronald DeFeo Jr. on six counts of second-degree murder. That morning about 800 mourners attended a funeral Mass at St. Martin of Tours Church in Amityville, where the Rev. James McNamara said: "I shall not try to give any explanation of the tragedy that has brought us here together ... my heart has been too heavy to seek an explanation."

DeFeo's insanity defense and the case goes Hollywood

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Ronald DeFeo Jr.'s trial began in October 1975, 11 months after the slaying of his family. His defense attorney, William Weber, tried to make the case that DeFeo Jr. was innocent by reason of insanity, but on Nov. 21, 1975, a jury found DeFeo Jr. guilty of six counts of second-degree murder. He was sentenced to six concurrent 25-year-to-life sentences.

In October 1977, Jay Anson, a documentary film writer, published his first book, "The Amityville Horror: A True Story." While writing the book, which became a bestseller, Anson interviewed members of the Lutz family, who moved into the house where the murders occurred in December 1975, but fled 28 days later, claiming the home was haunted.

By 1979, Jay Anson's book had been turned into a blockbuster movie of the same name starring James Brolin and Margot Kidder. It would be just one of several films crafted around the story. A prequel, "Amityville II: The Possession," came out in 1982, followed by 1983's "Amityville 3-D." More recently, Ryan Reynolds and Melissa George took on the roles of George and Kathy Lutz in a 2005 remake, which took even more creative liberties with the original story. And in 2013, one of the Lutz's three children, Daniel, released a documentary titled "My Amityville Horror."

What has happened with DeFeo since then?

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Ronald DeFeo Jr. was serving six concurrent 25-years-to-life sentences in Green Haven Correctional Facility in upstate Stormville. He was denied parole several times. In June 1992, DeFeo also appeared in court to request a retrial. He claimed his lawyer, William Weber, pursued an insanity defense against DeFeo's wishes to make the story more attractive to potential film producers. DeFeo told reporters: "He told me there would be a lot of money from book rights and a movie. He would have me out in a couple of years and I would come into all that money." On March 12, 2021, DeFeo was transferred to Albany Medical Center and was pronounced dead.

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