Max Shatto, born Maksim Kuzmin, and his younger brother Kristopher were adopted from an orphanage in north-west Russia last year by the Shattos, who live in Gardendale, Texas.
Four doctors in Texas concluded that Max Shatto, born Maksim Kuzmin, had died accidentally from a torn artery in his abdomen and had bruises consistent with injuring himself, a statement said.