The 21-year-old Pennsylvania man faces life in prison under the terms of the plea deal reached in court.
His cousin, Sean Kratz, is also expected to take a plea deal for his charges related to his involvement in the gruesome slayings of four boys who were found buried in DiNardo's farm last July.
Police found Thomas Meo, Jimi Patrick, Dean Finocchiaro, and Mark Sturgis five days after they were reported missing.
Three victims were discovered to have been lit on fire, and placed in a 12-foot deep oil tank converted into a pig roaster.
DiNardo was accused of luring the boys to his family's 90-acre farm in Bucks County under the pretense he would be selling them marijuana.
In December, DiNardo and Kratz initially pled not guilty to the murders.
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However, they later made the plea deal to avoid a death sentence.
DiNardo reportedly had a history with mental illness, but his lawyer, Fortunato Perri, said mental health professionals weren't certain they would be able to present an insanity defense.
As RadarOnline.com previously reported, DiNardo had a history of anger issues from an early age.
According to an insider, DiNardo was banned from school after various "verbal incidents," and showed violent behavior toward women.
According to sources close to DiNardo, a horrific ATV accident in 2016
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