Two people have been arrested on suspicion of the manslaughter of 39 people found dead in a refrigerated lorry in Essex.
The man and woman, both 38, from Warrington, Cheshire, were also held on suspicion of conspiracy to traffic.
Detectives are still questioning the lorry driver on suspicion of murder.
The victims – 31 men and eight women – are believed to be Chinese. They were found at an industrial estate in Grays at 01:40 BST on Wednesday.
Essex Police has been given extra time to question driver Mo Robinson, of County Armagh in Northern Ireland, who was arrested on Wednesday.
Post-mortem examinations are due to start later after the first 11 bodies were moved from Tilbury Port to Broomfield Hospital in Chelmsford.
The trailer arrived in Purfleet on the River Thames from Zeebrugge in Belgium at 00:30 on Wednesday.
It left the port shortly after 01:05 the same day and the bodies were found in the trailer at Waterglade Industrial Park about 30 minutes later.
Police said recovering the bodies would take time and the dignity of the victims was its primary concern.
The Chinese Ambassador to the UK, Liu Xiaoming, said he had sent a team to Essex to help verify the identity of the victims. He added that their nationality was yet to be confirmed.
Essex Police believes the lorry arrived in Holyhead in north Wales on Sunday, having travelled from Dublin.
Global Trailer Rentals Ltd told RTE News it owned the trailer and said it had been hired on 15 October.