She told investigators her son initially told her that he let the dog outside and it never came back.

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The boy's mother said a few weeks later, another dog vanished.

As the mother and her boyfriend started looking for the dog, they stumbled over a shallow grave in the backyard.

They discovered one of their dogs had been buried there with its head missing.

The mother's son admitted he killed the dog and buried it.

The boy, a Middleburg Elementary School student, is being held at the Duval Regional Juvenile Detention Center in Jacksonville.