Story highlights Two boys plot to kill a girl outside their Washington state school unravels

The boys also intended to kill six more students one by one, authorities say

One boy was going to stab the girl; the other was to use a gun to guard him

One boy stole the gun from his older brother, who in turn stole it from dead grandfather's home

Two fifth-grade boys armed with a stolen semi-automatic gun, ammunition clip and knife plotted to kill a classmate in Washington state but were thwarted when another student informed a school employee, authorities said Thursday.

The two boys, who told police they considered the girl rude and annoying, won't be tried as adults and will be in court next Wednesday for a capacity hearing, said Tim Rasmussen, the Stevens County prosecuting attorney.

The two boys, ages 10 and 11, told authorities that they were also going to kill, or "get," six more students at Fort Colville Elementary School in Colville, Washington, and even identified them from a class list provided by school employees, according to court documents.

The boys' plan called for the older to stab the girl off-campus with a 3.25-inch knife last week, and the younger boy would scare off any responders with a .45-caliber Remington 1911 semi-automatic handgun, court documents said.

The younger boy had been in "a short dating relationship" with the girl, but he told authorities that "she's rude and always made fun of me and my friends," court papers said.

"Yes, I just want her dead," the younger boy told authorities. He brought the gun and knife to school, documents said.

The older boy had been friends with the girl for several months, but he wanted to kill her because she picked on and annoyed him, court papers said.

"Yes, and I wanted to kill her alone at first," the older boy told a police officer.

The officer noticed in his interview with the older boy that he "did not display any emotion or remorse during the interview," court papers said.

The younger boy took the gun from his older brother by finding a hidden key to the gun case kept in the brother's bedroom, and the older brother told authorities that he stole the firearm from their dead grandfather's home, court papers said. The older brother is also a juvenile, Rasmussen said.

The two boys told another student two weeks earlier about the plot to kill the girl and were going to pay him $80 to keep it secret, the court filings said.

The two boys were going to kill the other six students by luring them away from school one at a time, court papers said.

When authorities were transporting the arrested boys to the Stevens County Courthouse, the juvenile probation department staff told a detective that they overheard the older boy telling the younger: "If I find out who told them about our weapons, I'm going to kill them. I don't care; when I get out of jail I'm going to come back and kill them," according to court papers.

Under Washington state law, children between the ages of 8 and 12 are presumed to not have a capacity to commit a crime, prosecutor Rasmussen told CNN.

"What this hearing will determine is they will look at certain factors and try to get these children under the jurisdiction of the juvenile court," Rasmussen said about next week's proceedings.