A 7-year-old boy was attacked and killed by his family's newly adopted rescue dog.

James McNeelis, from Kiefer, Oklahoma, was reported missing by his family on Wednesday night at 7:20 p.m. to the Creek County Sheriff’s Office. The family said that they realized he was missing when he did not come home for dinner or return any phone calls.

When officers arrived at the scene, James’ father, Michael McNeelis, had found his son dead in the family’s backyard.

An investigation concluded that their Shetland Sheepdog-Corgi mix, who was only adopted three weeks earlier, had fatally attacked the boy. He was pronounced dead at 7:35 p.m. local time, according to the sheriff’s office statement.

Shannon Edison, a neighbor to the family, told KOTV, a CBS affiliate in Tulsa, that she heard a very loud scream and knew something was wrong.

“It was a very, very life-changing scream, if that makes sense,” Edison said. “We knew something was wrong. As a mother, you know that scream. If anybody’s ever heard that scream, you know that scream. Something was catastrophically wrong.”

The family told KJRH, an NBC affiliate in Tulsa, that they had taken in the dog as a stray and that it did not show any signs of aggression before the attack.

“He was so full of life and light and he was going to change the world. And he still is. His light will change the world,” James' father posted on Facebook.

“We feel alone and lost without him and we’re doing all we can but it’s just hard. Everything just hurts without my little boy here.”

The sheriff’s office said in a statement that the dog was being held at an animal control facility. The condition of the dog has not been reported.

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