Thirteen children aged as young as one were among the Afghan immigrants rescued from a shipping container.
Thirty of the 35-strong group found screaming and banging at the Port of Tilbury are 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 aged between one and 12.
It was also revealed that the man who died after the container was opened - prompting a homicide investigation - is believed to have been in his 40s.
A post-mortem examination was carried out but further tests are set to be undertaken to establish the cause of death.
Four others remain in Southend Hospital.
A statement issued by police said the 30 people who have been released from hospital after being treated for hypothermia and dehydration are still being spoken to "about their ordeal".
It was disclosed earlier that the immigrants are Sikhs who are understood to be from Afghanistan.
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.
A spokesman for the Federal Police in Belgium, said it appeared to be "impossible" for the 35 to be loaded into the unit in the time it was at Zeebrugge.