(CNN) A 77-year-old British man admitted Monday to killing his 6-year-old great-grandson, who died after being shot with an air rifle.

Albert Grannon, 77, from the village of Sproatley in East Yorkshire in northern England, pleaded guilty to manslaughter and possession of a firearm without a certificate. His grandson, Stanley Metcalf, died after he was shot on July 26, 2018.

Grannon entered his plea at Hull Crown Court and will be sentenced following presentence reports at a later date.

"This was an extremely tragic incident where a 6-year-old boy who had all his life ahead of him had it cut so needlessly short," said Detective Inspector Rebecca Dickinson in a statement . Dickinson led the investigation for Humberside Police.

"It makes it all the more tragic that it was a member of his own family who was ultimately responsible for his untimely death," she said.

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