Peter Kema Sr. passed a polygraph test about his statements to police on where he disposed of his 6-year-old son’s body 20 years ago, as part of a plea deal, a police source said.

Kema told Hawaii County police that he dumped the boy’s body into the ocean in Puna.

Peter “Peter Boy” Kema died in 1997 of septic shock after years of abuse by his father and for his parents’ failure to get medical attention, prosecutors said. The Kemas kept the secret of his whereabouts and circumstances of his death for nearly 20 years.

In 2016, both parents were indicted on second-degree murder charges, and both accepted plea deals.

Peter Kema Sr. accepted a plea deal, pleading guilty to manslaughter on April 5, which carries a 20-year sentence.

As part of the plea deal, Kema had to reveal where he disposed of the boy’s body. If the boy’s remains could not be found, he had to pass a lie-detector test.

After searching for several weeks, police, Coast Guard and Department of Land and Natural Resources personnel could not find the remains.