Sikhs, discovered at Tilbury Docks in Essex, east of London, feared they would have all died had they remained inside for any longer without food or water, Kamaljit Singh Mataharu, a Punjabi-speaking local man called in by the police to translate, told reporters.
"It was pitch black, without any air. It soon became extremely uncomfortable," he told ITV television. "Horrendous, horrendous, horrendous. They suffered a lot," he said.
It has emerged that there were 15 families inside the container, all from Kabul, who had made it to Europe in a truck. A 40-year-old man died and the survivors included 13 men, eight women, aged between 18 and 72, and 13 children aged between one and 12.
"They were in a bad state. According to a little boy they'd been in the container for roughly 18 hours," said Mataharu. The container had arrived on a truck at Zeebrugge 12 hours before the people inside were discovered at Tilbury.
"They'd been banging on the container... they'd tried for hours and hours for somebody to hear their voices. They are thanking God they are alive. Another 20 minutes... all would've been dead in there," the translator said.
Earlier, footage of the group showed at least 13 children, including one as young as one-year-old, were part of the group. The illegal immigrants from Afghanistan were found screaming and banging for help inside the container on Saturday.
The officer leading a homicide inquiry after the man's body was found inside along with 34 other people said members of the Sikh community from Tilbury were assisting officers and helping to care for the stowaways.
They were hospitalised and those released from hospital include nine men and eight women and 13 children. Four survivors still remain in Southend hospital. A post-mortem examination was carried out on the body of the deceased yetserday but further tests are set to be undertaken to establish the cause of death.
The Sikh families are believed to be escaping persecution in Kabul by Islamist extremists. Bhai Amrik Singh, chair of the Sikh Federation (United Kingdom), said,"It is a disgrace the persecution of the tiny minority of Sikhs from Afghanistan has largely been ignored and it takes an incident like this to remind us all that they are also being exploited by human traffickers.
"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," said Superintendent Trevor Roe of Essex police.
There were fears that another container with people inside may have arrived on the ship, but no one else was found after all the ship's containers were searched. The container was on a P&O-owned commercial vessel, the Norstream, that carries freight between Zeebrugge in Belgium and Tilbury.
Peter De Waele, a spokesperson for the federal police in Belgium, said it appeared to be impossible for the 35 people to be loaded into the container in the time it was at Zeebrugge, a port in the north of the country.
Sikhism is a minority religion in Afghanistan, and the population is limited to a few thousand. Many have fled since the Soviet invasion in the early 1980s, when the population stood at more than 100,000.
Sikhs in the country have previously complained they are ostracised.
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