A wrongful death lawsuit was filed on behalf of the estate of "Peter Boy" Kema on Wednesday.
Half-siblings Chauntelle, Allan, and Lina Acol are suing the boy's father, Peter Kema Sr., their mother, Jaylin Kema, the State of Hawaii, and the Department of Human Services.
"Peter Boy" was 6 years old when his parents claimed he disappeared back in 1997.
Prosecutors believed he died of sepsis from untreated injuries received from his father, who later admitted he burned his body and dumped his bones in the ocean.
Peter Kema Sr. pleaded guilty to manslaughter last year, receiving a 20-year prison sentence. Jaylin Kema also pleaded guilty to manslaughter. She received 10 years of probation.