SEATTLE - Prosecutors are expecting the police investigation into a shooting at a Washington elementary school to include a harder look into what role adults played in a 9-year-old boy bringing a gun to school.

Charging documents showed the boy obtained the .45-caliber handgun during a visit with his mother, Jamie Lee Chaffin. The gun discharged in his third-grade classroom, critically wounding an 8-year-old girl.

"I fully expect all aspects into the case to be investigated," Kitsap County Deputy Prosecutor Ione George said Friday, adding that her office is "interested" in how the boy obtained the gun.

So far, only the boy has been charged - with unlawful possession of a gun, bringing a dangerous weapon to school and third-degree assault. Bremerton police have remained mum on the investigation and how much of a focus is on the boy's mother.

"I'm getting that question quite a bit," said Lt. Peter Fisher. "I'm not able to comment on that until the investigation is complete."

Authorities said the weapon discharged from inside the boy's backpack just before classes let out Wednesday, and a bullet struck Amina Kocer-Bowman in the arm and abdomen.

Harborview Medical Center spokeswoman Susan Gregg said Kocer-Bowman underwent another surgery Friday and remains in critical condition.

"She'll have multiple surgeries moving forward," Gregg said.

The boy has left the juvenile detention facility after someone posted $50,000 bail, said Todd Dowell of Kitsap County prosecutor's juvenile division.

At a court hearing Thursday, Kitsap County officials said the boy's parents had extensive criminal records.

Court documents show Chaffin sued the boy's father - Jason Cochran - for failing to pay child support. She also has been in and out of the court system, according to court documents. In 2005, she was arrested for possession of methamphetamine in Bremerton but pleaded guilty to a drug paraphernalia charge. She also was convicted of marijuana delivery and forgery.

Jason Cochran has been convicted multiple times for violating protection orders regarding Chaffin.

Cochran and an uncle attended Thursday's court hearing and apologized to girl's family. Cochran said the gun belongs to Chaffin's boyfriend and said he wants police to investigate her.

"I've called to (his) mother. She won't accept my calls," Cochran said.

While charges have been filed against the boy, the child will not be arraigned until the court determines whether he has the capacity to understand that what he did was wrong.

Under state law, children between 8 and 12 years old can face charges if a court makes such a determination. A capacity hearing in this case will be scheduled in two weeks.