The "Amityville Horror" killer who shocked the nation when he went on a killing rampage died in the Hudson Valley.

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Ronald DeFeo Jr. died Friday at the age of 69 while serving six 25-year-to-life sentences at the NYS DOC Sullivan Correctional Facility in Fallsburg, the New York State Department of Corrections confirmed over the weekend.

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On Nov. 13, 1974, DeFeo Jr. killed his 43-year-old father, Ronald DeFeo Sr., 43-year-old mother Louise DeFeo, 9-year-old brother John, 12-year-old brother Marc, 18-year-old sister Dawn and 13-year-old Allison inside their Long Island home.

DeFeo Jr. was 23-years-old when he used a .35-caliber Marlin lever-action rifle to murder his father, mother, two brothers and two sisters as they slept in their Amityville.

In 1975, he was convicted on six counts of second-degree murder and received six sentences of 25 years to life. His story inspired the book and movie versions of "The Amityville Horror."

He's been serving his life sentence at the maximum-security prison in the Hudson Valley.

DeFeo Jr was pronounced dead at Albany Medical Center after being transferred from the Sullivan County prison, according to the New York Post. A cause of death hasn't been released as officials wait for autopsy results.

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