Steven Avery Molested Brendan Dassey To 'Keep Him Quiet' In Murder

In his new tell-all about Making a Murderer's infamous case, prosecutor Ken Kratz makes the shocking allegation that Brendan Dassey accused his killer uncle Steven Avery of sexual abuse.

"Brendan made those allegations against his uncle Steven on the phone to his mother," the Avery: The Case Against Steven Avery and What Making a Murderer Gets Wrong author, 57, tells RadarOnline.com in an exclusive video interview. "He made them to law enforcement officers. He made those allegations several times, that's why I included it."

Kratz insists he didn't include the claim to shock or horrify readers. Rather, he thought it was an important detail about the sick uncle/nephew duo's complicated relationship. (As RadarOnline.com readers and Making a Murderer fans know, Avery, 54, and Dassey, 27, were infamously convicted in the October 31, 2005 rape and murder  of 25-year-old Teresa Halbach on the family's Wisconsin property.)

"This was another way to keep Brendan quiet," Kratz explains. "A way to buy his silence."

Two years later, both men were sentenced to life in prison.

Kratz also claims in his book that Avery was accused of raping a teen niece in the summer of 2004, and sexually assaulting a young babysitter in the 1980's. Neither detail was included in the Netflix hit show.

While Avery's new attorney is planning a new appeal in the decade-old case, Dassey's conviction was overturned in August 2016. He will remain incarcerated pending an appeal.