5 year old Billings, Montana boy shot accidentally by 8 year old boy

What are 2 little boys doing with a gun unsupervised by an adult in a park in the Billings, Montana area? A 5 year old boy was found lying in the grass in a dog park by two girls passing by on their bikes. From the article:

"I just saw a boy who was covered in blood and moaning, and a girl who looked up at me bawling,” Crawford said. “I didn’t know what to think. I just tried to keep the boy calm.”

Brewer said the boy suffered a gunshot wound in the lower abdomen and it appeared that the boy had been shot at least 15 minutes before the girls found him. He was taken to St. Vincent Healthcare and underwent surgery. Police said he was in stable condition in the hospital's pediatric intensive care unit.

At about 8 p.m., authorities were able to locate the suspect, an 8-year-old boy, at his home. He was transported to the Police Department with a parent to be interviewed.

A small-caliber gun and ammunition was found at the scene, Brewer said. He doesn’t believe anyone would have heard the gunshot because that type of gun doesn’t make a loud shot.

It is unclear where the boys got the gun, Brewer said.

Every gun in the hands of a child or teen must first pass through the hands of an adult.