At least 35 Afghan Sikh immigrants, including thirteen children between the age of one and 12 were reportedly found in a shipping container at Tilbury Docks.
According to the BBC, Essex Police said the group arrived on Saturday on a ship from Belgium and were believed to be victims of "people trafficking".
While one man was found dead, the remaining were taken to a hospital for treatment of severe dehydration and hypothermia.
Nine men and eight women between the age of 18 and 72 are among the 30 people released to the police so far.
The police said the victims have been taken to a makeshift reception centre set up inside the terminal buildings at Tilbury Docks, and are being spoken to about their ordeal, before they are handed over to the UK Border Force.
Throwing light over the frequent verbal and physical abuse faced by the Sikh community in Afghanistan, Immigration lawyer Harjap Singh Bhangal, said that the number of Sikh families in the country had been dwindling.
He further said that as a result of abuse, Sikhs are leaving Afghanistan for other countries in Europe such as Germany, France and the UK.