Thirteen children aged between one and 12 were among 35 Afghan Sikh immigrants found in a shipping container at Tilbury Docks, according to police.
The group arrived on Saturday on a ship from Belgium and were said by police to be victims of “people trafficking”.
Thirty of the 35-strong group found screaming and banging at the Port of Tilbury were yesterday being quizzed by officials after being released from hospital. Essex Police said they include nine men and eight women aged between 18 and 72 as well as 13 children.
It was also revealed that the man who died after the container was opened is believe to have been in his 40s. A post-mortem examination was carried out yesterday but further tests are to be undertaken to establish the cause of death.
Four others remain in Southend Hospital and were expected to be kept in for a second night.
Superintendent Trevor Roe, of Essex Police, said: “The welfare and health of the people is our priority at this stage.
“Now they are well enough, our officers and colleagues from the Border Force will be speaking to them via interpreters so we can piece together what happened and how they came to be in the container.
“We now understand that they are from Afghanistan and are of the Sikh faith. We have had a good deal of help from partners within the local Sikh community in the Tilbury area to ensure that these poor people, who would have been through a horrific ordeal, are supported in terms of their religious and clothing needs.”
A post-mortem examination of the man was being conducted yesterday while the container in question was being examined by forensic experts. Police believe substances found in the container are cleaning chemicals which are not thought to pose a health risk.
All of those rescued from the container will be taken care of by the Border Force in a “suitable location” once officials have finished questioning them. The Red Cross provided food and welfare for the group overnight.
The port has resumed business as usual, while police dismissed concerns that a further container with people inside may have arrived at Purfleet.
Belgian police earlier indicated that they believe the immigrants were probably already inside when it was dropped at a European port before setting sail for Britain. Peter De Waele, spokesman for the Federal Police in Belgium, said investigators are “very hopeful” that they can track down the driver and company of the vehicle that deposited the container.