Story highlights

NEW: Juvenile detention superintendent says the boy is being held in a pod with up to 16 juveniles

MaKayla "BooBah" Dyer, 8, was shot and killed last Saturday; an 11-year-old boy is charged in her death

"I want her back in my arms, this is not fair," the girl's mother says

White Pine, Tennessee CNN  — 

As a Tennessee community prepares to bury a girl allegedly killed by an 11-year-old boy over a puppy, more details emerged about the gun used in the shooting.

That’s what Jefferson County, Tennessee, Sheriff G.W. “Bud” McCoig said led to the Saturday death of 8-year-old MaKayla “BooBah” Dyer.

McCoig told CNN’s sister network HLN that an 11-year-old boy asked to see the girl’s puppy.

When she said no, the boy got a gun and shot her dead Saturday, according to the sheriff.

The 11-year-old is being held on a first-degree murder charge in a juvenile detention center. The superintendent of that facility, Richard Bean, said that the boy – the youngest ever held there on a murder charge that he knows of over his 44-year career – is being held in a regular “pod” that holds up to 16 other juveniles who are between the ages of 12 and 17.

Bean described the boy as “very tiny,” weighing about 55 pounds.

“It is the most pitiful case on both sides,” Bean said.

The Jefferson County District Attorney’s Office will determine whether the boy should be tried as an adult.

“We don’t have situations like this,” the prosecutor said. “… So it is very difficult.”

He is being detained until a hearing on October 28, his public defender, Edward Miller, told CNN affiliate WATE. He declined to comment further.

‘I want her back home’

MaKayla died three weeks after her 8th birthday.

Kids and guns: ‘These are not isolated tragedies’

“My heart is aching because a little girl lost her life really young,” Chasity Arwood, a neighbor of both the victim and the accused, told WATE. “My heart is aching, too, because a little boy is having to go through what he’s having to go through.”

The slain girl’s mother, Latasha Dyer, choked back tears as she talked to the same news station.

“I want her back home, I want her back in my arms,” she said. “This is not fair.”

Hundreds attended a visitation for her Wednesday evening in Maynardville, where songs from the Disney hit movie “Frozen” were played – just like MaKayla would have liked.

“She was a lovable, little, adorable and typical 8-year old girl that enjoyed life and loved everybody,” great-uncle Kenneth Norton told CNN. ” She didn’t know (any) strangers … and anytime that you were doing anything … she wanted to be a part of it.”

CNN’s Greg Botelho reported and wrote from Atlanta, and CNN’s Victor Blackwell reported from Tennessee. CNN’s Gigi Mann, Jean Casarez and Cortney Peltz, from CNN’s sister network HLN, contributed to this report.