COLVILLE, Washington (AP) - A north-east Washington state judge has found two boys, aged 10 and 11, competent to stand trial in juvenile court on a murder conspiracy charge.

Stevens County Prosecutor Tim Rasmussen said the fifth-graders had a handwritten plan listing seven steps leading up to the planned killing of a female classmate. That list was submitted as evidence at their mental capacity hearing on Friday.

A county judge ruled that the boys understood the nature and consequences of their actions. They pleaded not guilty to conspiracy to commit murder, witness tampering and juvenile possession of a firearm.

The boys were arrested on Feb 7 at Fort Colville Elementary School after a fourth-grader saw one playing with a knife on a school bus and told a school employee. A backpack search also turned up a .45-caliber semi-automatic pistol and ammunition.

The Spokesman Review reports that the boys are being held on US$100,000 (S$124,101) bond each. Both a defence psychiatrist and a state psychologist said they present a danger to the community.