WAILUKU - The grandmother and sister of a 4-year-old boy who was killed two years ago are suing the state and its Department of Human Services, alleging negligence by the agency in returning the child to his parents' custody despite acts of violence beginning shortly after his birth.

The lawsuit, filed Friday in 2nd Circuit Court, also alleges that Child Welfare Services failed to protect Zion McKeown and didn't fully investigate or take action on reports of neglect and abuse inflicted on the child by his parents.

Zion died in the early-morning hours of May 30, 2012, after he was taken to the Maui Memorial Medical Center emergency room the night before by his father, Kyle McKeown, and the father's live-in girlfriend, Grace Lee-Nakamoto. The boy had been living with his father and Lee-Nakamoto at a Wailuku apartment complex.

Preliminary autopsy findings showed injuries to his abdomen were most likely caused by "someone stomping on him while he was lying on the ground," according to a court affidavit. Zion also had numerous bruises and abrasions to his arms, legs, face, back, chest, neck and the back of his head that had been caused just before his death, the lawsuit says.

McKeown, 34, and Lee-Nakamoto, 29, are each charged with second-degree murder and are awaiting trial.

Kayla Rosenfeld, public information officer for the state DHS, said Friday that she hadn't seen the lawsuit and declined comment. "We don't comment on any ongoing cases involving Child Welfare Services due to confidentiality," she said.

Honolulu attorney Carl Varady filed the lawsuit on behalf of Maryann Rooney, Zion's maternal grandmother, and his older sister, a minor identified as I.P.

According to the lawsuit, Zion's mother temporarily lost custody of the boy after he was treated at Kapiolani Medical Center for Women and Children in March 2008 for multiple fractures of his ribs. Zion, who was not yet 4 months old, also was suffering seizures.

Zion's mother had previously been reported to Child Welfare Services for issues relating to the care of her daughter, I.P., who had been placed with her grandmother for eight months, the lawsuit says.

Starting in 2007, Zion's mother could visit her daughter only under Child Welfare Services supervision or with Zion's grandmother or another approved adult, according to the lawsuit.

The lawsuit says Zion was returned to his parents, even though Child Welfare Services knew "that he had suffered injuries, including multiple broken bones and seizures while in his parents' custody."

"Because of the abuse inflicted on him by his parents from infancy, Zion was deaf and could not speak for himself," the lawsuit says. "Zion's parents began abusing him immediately after he was returned to their custody."

Both Rooney and another adult reported the abuse, the lawsuit says. Zion and his parents had been living on Oahu. The lawsuit says McKeown moved to Maui to evade investigation by Child Welfare Services. Zion went to live with his father on Maui in 2011, according to the lawsuit.

The lawsuit seeks unspecified damages.

* Lila Fujimoto can be reached at lfujimoto@mauinews.com.