LONDON -- Police investigating the death of a migrant inside a ship's cargo container say the victim and 34 survivors are Afghans from the country's tiny Sikh community.

Essex Police Superintendent Trevor Roe said Sunday it took a day to determine the stowaways' nationality because of language difficulties and lack of documentation. Police initially thought they were Indian.

Dock workers at Tilbury, a port east of London, found the 34 survivors screaming and pounding the walls inside the container Saturday. Paramedics declared one man dead and treated others for hypothermia and dehydration.

Essex Police say the migrants included 13 children, and ranged in age from 1 to 72.

Belgian police say they are tracing movements of the truck that delivered the container, with the Afghans presumably inside, to a Belgian port Friday.