HILO, BIG ISLAND (HawaiiNewsNow) - It's been 19 years since 6-year-old "Peter Boy" Kema Jr. disappeared on Hawaii Island. His body was never found.
Those two factors are going to make the case against his parents — indicted Thursday in his murder — a significant challenge, defense attorneys say.
"This (requires) proof beyond a reasonable doubt. This is murder," said defense attorney William Harrison. "And they're gonna have a hard time with that."
Peter Kema Sr. and his wife, Jaylin, pleaded not guilty in court on Friday, and requested jury trials.
On Thursday, the couple was indicted by a Hilo grand jury, a major breakthrough in one of Honolulu's most well-known unsolved murder cases.
Peter Boy disappeared in 1997, after years of child abuse at his parents' hands that had been well-documented by state Child Protective Service workers.
The key witnesses in the case against his parents: Their other children. That's why a judge has ordered Peter Kema Sr. to stay away from them should he bail out of jail.
Two of Peter Boy's siblings told Hawaii News Now last year that they hoped their mother would turn on the father, who they believe killed Peter Boy.
Lina Acol, who was 4 when Peter Boy disappeared, now has a son of her own and hopes Jaylin Kema will make a deal with prosecutors.
Without such a deal, attorneys say the case will be an extremely difficult one for prosecutors.
"I think they're going to have serious problems with this case," said defense attorney Victor Bakke. "There's no conclusive evidence the child is dead."
But getting a murder conviction without a body isn't unprecedented.
In 2008, Kirk Langford was convicted for murdering a Japanese tourist in Pupukea, even though her body was never found.
Former Honolulu Prosecutor Peter Carlisle tried the case, and acknowledged it was a gamble. But, he added, he believes Hawaii County prosecutors can win the case against Peter Boy's parents.
"The key to this case is circumstantial evidence," he said. "You prove that Peter Boy Kema is dead and gone. After 19 years that isn't hard to do. He isn't coming back."
Carlisle says a jury would find it reasonable that it was the Kemas' duty to make sure Peter Boy was safe.
The indictments against the couple say the parents "intentionally or knowingly" caused Peter Boy's death because they didn't get needed medical care for him, though he was the victim of "multiple crimes of assault" and "was suffering from serious physical harm."
State documents show that Peter Boy was repeatedly abused by his father. At just 3 months old, he was brought to Hilo Hospital with multiple new and healing fractures.
But, defense attorneys say, that doesn't mean Peter Kema Sr. killed his son.
Bakke added that the case could also hinge on emotion — and that would be a plus for the defense. The case is notorious in Hawaii, and many Hawaii Island residents know the family involved.
"Anytime a child is a victim of a crime as heinous as this is alleged, that brings up raw emotions," Bakke said.
Mobile users: Click here to see a timeline of Peter Boy's life and the investigation into his disappearance.