The arrow, fired by a 13-year-old, entered the left side of 10-year-old Austin Almanza in the area of his lower torso, Lincoln County Sheriff Charlie Dougherty said at a news conference Monday. It exited on the other side.
The arrow kept traveling and stuck in the arm of Austin's brother, Ayden, 8, who was standing just to the side Austin.
Austin was pronounced dead on the scene, Dougherty said. Ayden was treated at a hospital and released.
Oklahoma News4 reported some of the text of the 911 call.
"Dispatch: 911. 'Can I help you?'
"Caller: 'One of the neighbors . . . I guess an arrow went through one of the kids and stuck in the other one.'"
"Dispatch: 'I need everybody there to calm down. I need you guys to try and get the people that are injured to sit down and be still.'
"Caller: 'I've got him calmed down. The other one is over in the bushes.'
"Dispatch: 'We have everybody headed your way.'
The name of the 13-year-old was not released because he is a juvenile. No charges have been filed so far, though the boy is in custody. No information was available about the type or brand of the crossbow, which come in many forms with different degrees of power and range.
While the projectile fired was described as an arrow, some types of crossbows fire bolts.
Dougherty said the crossbow shooting was not an accident.
"Ten-year-old Austin's not dead because of an accident," he said. "He's dead because of an action that took place. . . . We are investigating it as a homicide."
Dougherty said the boys were friends who often played together in the treehouse near a vacant lot in the neighborhood.
While he said he was unaware of any particular bad blood between the boys, Dougherty said investigators believe that some sort of "disagreement" led up to the incident. Right now, he said, deputies are getting "conflicting" stories from the boys and are still piecing together how the tragedy unfolded.
The two victims attend White Rock Elementary School in the town of McLoud. The superintendent, Bob Gragg, told NewsOK that they were "very well-mannered, very polite young men."
"We're certainly heartbroken and saddened on behalf of the school community and certainly the family," he told the station. "We're just a small school, a small community and it hits hard just like it would in any family."
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)