The 39 people found dead in a refrigerated trailer in Essex were Chinese nationals.
The police is moving on with the investigations, accusing the lorry driver, Mo Robinson, 25 years-old, on suspicion of murdering eight women and 31 men.
Officers from Northern Ireland have raised three properties and the National Crime Agency is trying to identify the “organised crime groups who may have played a part.”
The trailer was coming from Zeebrugge, in Belgium, and arrived at Purfleet, on the River Thames.
The bodies were discovered by the ambulance int he container at Waterglade Industrial Park, in Grays, after 1:30 BST on Wednesday.
The lorry and trailer left the port at Purfleet shortly after 01:05.
Police said the tractor unit – the front part of the lorry – entered the country via Holyhead in Wales on Sunday, having travelled from Dublin.
The lorry is now being moved to a secure site in Tilbury Docks, to keep conducting the investigations and to give the “utmost dignity to those within the trailer.”