HILO >> Peter “Peter Boy” Kema Jr. should have been preparing to celebrate his 26th birthday on May 1.

Instead, his 46-year-old father is expected to have led police to his remains by then. Peter Boy never lived to see his 7th birthday, and his little-boy smile is etched in the memories of people who have asked for the past 20 years, “So where’s Peter?”

After 20 years of silence, Peter Kema Sr. accepted a plea deal Wednesday and told a Hilo Circuit Court judge he was guilty of the lesser charge of manslaughter rather than murder in the death of his youngest child.

Kema’s admission includes that he caused the child’s death “by omission” for failing to obtain medical services for his son, for recklessly causing his death by the multiple assaults upon him, and for failing to get help from law enforcement and medical personnel.

In exchange for his guilty plea, Kema has agreed to lead authorities to his son’s remains. If the body cannot be found, he must pass a polygraph test.

He also pleaded guilty to hindering prosecution of his wife, Jaylin Kema, 47, who agreed to testify against him if the case had gone to trial.

Deputy Prosecutor Rick Damerville said after the hearing that the decision to offer Kema a plea deal on manslaughter rather than murder had to be agreed upon by everyone, including the Kemas’ three surviving children. Otherwise, he told them, “If you people don’t agree with me, I’m going to trial.”

Kema will be sentenced at 8 a.m. June 9 to 20 years for manslaughter, rather than life imprisonment for murder, and five years for hindering prosecution, with a minimum mandatory sentence of six years and eight months.

Kema, who was indicted on a charge of second-degree murder and arrested in April 2016, was supposed to be tried by a jury April 25, and Damerville said he was prepared to go to trial because he thought Kema might have backed out of the deal Wednesday.

Judge Greg Nakamura asked Kema whether he was aware that the time limit had expired to bring forth the manslaughter charge.

A gray-haired Kema, wearing an orange jumpsuit and handcuffs, calmly answered yes and appeared to slightly smile when speaking to the judge. In contrast, Kema in 1998 told the television-viewing public that he had taken his son to Honolulu and left him with “Auntie Rose Makuakane” in Aala Park. No evidence of such a woman was ever found.

Had Kema refused to take the plea deal, he would have gone to trial on the murder charge and could have rolled the dice that the jury would have found him not guilty of murder, Damerville said. He also could have opted to ask the judge to instruct jurors on the charge of manslaughter.

Damerville said he did not get the case until March 2016 but that the 10-year statute of limitations for manslaughter had expired in 2007. (There is no time limit for a murder charge.)

“In 2007, we were still dealing with, ‘Is this boy still alive?’” he said, adding that developments in 2011 and 2016 have made the case much easier to prosecute.

Police will now take statements from Kema as to what really happened and have him lead them to the remains.

Damerville said they have an idea of where the body is but did not release any location for fear “amateur hunters” may go searching.

For Capt. Randall Medeiros, who was a 28-year-old detective at the time of the boy’s disappearance, it is one of two cases that will forever stay with him. “My son was roughly the same age,” he said.

He said the plea provides relief and some sense of satisfaction for the many police officers who have worked on the case, many of whom have since retired.

Medeiros has been on the case these past 20 years and said that police knew soon after the investigation began that it was not a missing-person case, but a homicide. “Just following the evidence, it led us to this conclusion fairly early on.” The status of the case didn’t change, however, until 2000.

“It’s a relief that we now know we were right,” he said.

Two of Peter Boy’s three siblings, who were also abused by their father, attended the hearing. Sister Lina Acol and brother Allan Acol, their maternal grandfather James Acol and maternal aunt sat in the courtroom gallery.

Hawaii County Prosecutor Mitch Roth said James Acol, who had promised his late wife he would see this through and find the body, broke down privately after the hearing, and none of the family members wanted to address the media.

But he said the plea was what the family wanted for closure.

“It’s a 6-year-old boy that died here,” he said. “This is a tragedy all the way around. … We’re pleased to have resolution. The family seems pretty satisfied, but it’s still a difficult situation. It’s still a dead child.”

The family likely will address the court at sentencing, prosecutors said.

Prosecutors say that Jaylin Kema does not know where Peter Boy’s remains are but may have a general idea.

Medeiros said, “There are too many variables to say whether we’ll be able to recover the body,” including Kema’s memory, whether the body was buried or just placed on the ground, and the condition of the remains.

Steve Lane, appointed special master by a Family Court judge on behalf of Peter Boy’s siblings interested in pursuing a civil lawsuit for their dead brother, said after the hearing, “Astonishing outcome, given the evidence. That’s not murder, not even close.”

“Had they gone to trial for murder, he would have walked,” he said.

Lane, a private investigator, praised Damerville.

He said Peter Boy’s siblings are “nice kids, well mannered and sweet,” despite coming from “horrific circumstances.”

He attributed that to their grandparents, who took them in and raised them.

Jaylin Kema, who accepted a plea deal for manslaughter in exchange for agreeing to testify against her husband, will be sentenced May 30. But she is scheduled to be released before then — on April 27 — after serving one year.