Detectives investigating the deaths of 39 people found in the back of a lorry in Essex have been given an extra 24 hours to question the driver.
A 25-year-old man, named locally as Mo Robinson, from Northern Ireland was arrested on suspicion of murder and remains in custody.
Officers were granted a warrant to hold him for more time by magistrates in Basildon, an Essex Police spokeswoman said on Thursday.
Earlier it was confirmed that the eight women and 31 men found in the vehicle on an industrial estate in Grays were all Chinese.
Yesterday, police searched three addresses in Northern Ireland as part of the investigation.
Councillor Paul Berry said the village of Laurelvale, near Portadown, where the Robinson family live, was in “complete shock”.
The discovery echoes one in 2000 when the bodies of 58 Chinese illegal immigrants who had paid a criminal gang to be smuggled into the UK were found in a sealed, airless container in Dover.
Essex Police Deputy Chief Constable Pippa Mills said: “This is an incredibly sensitive and high-profile investigation, and we are working swiftly to gather as full a picture as possible as to how these people lost their lives.
“Our recovery of the bodies is ongoing and the post-mortem and identification processes, which will be lengthy and complex, can then begin.”
Home Secretary Priti Patel met with officers from the force to be updated on the investigation and local dignitaries and police gathered to open a book of condolence.
The trailer containing the 39 dead arrived at Purfleet from Zeebrugge in Belgium at around 12:30am on Wednesday, and the front section to which it was attached, known as the tractor, came from Northern Ireland via Holyhead in North Wales on Sunday.
The lorry and trailer left the port at Purfleet shortly after 1:05am and officers were called around 30 minutes later after ambulance staff made the discovery at Waterglade Industrial Park in Eastern Avenue, Grays.
The deaths follow warnings from the National Crime Agency (NCA) and the Border Force of the increased risk of people-smuggling via Belgium and into quieter ports such as Purfleet.
The NCA previously said it had a “greater focus” on rising smuggler numbers in Belgium after the closure of a migrant camp, and a Border Force assessment highlighted Zeebrugge as being among “key ports of embarkation for clandestine arrivals”.
The NCA has also warned that criminal networks are suspected to have started targeting quieter ports on the east and south coasts of the UK as well as the main Channel crossing between Calais and Dover.
The lorry has been moved to nearby Tilbury Docks so the bodies could be recovered.
A port official suggested yesterday the container may not have received an internal check as it passed through Belgium to the UK.
Joachim Coens, chief executive of Zeebrugge port where the lorry trailer departed from, said it was unlikely people were loaded into the container at the Belgian site.
He told the Flemish TV channel VRT: “A refrigerated container in the port zone is completely sealed.”
Mr Coens added: “During the check, the seal is examined, as is the licence plate. The driver is checked by cameras.”
Under EU rules, internal trading borders are effectively abolished between member states in relation to the trade of goods, with no duties paid when goods are transported from one EU country to another.
Custom authorities are meant to work together to ensure the rules of the internal market are enforced and to prevent people-trafficking.
But experts have questioned the strength of customs checks in Europe following the grim discovery of the lorry full of bodies in Essex.
On Wednesday, Richard Burnett, chief executive of the Road Haulage Association, said drivers had to continuously guard themselves against the risk of people smugglers targeting their vehicles.
He said: “They have to be very careful about where they park up, they have to be very careful about checking seals on their trailers to make sure nobody has broken in.”
Mr Burnett also highlighted that robust checks at Calais and Coquelles in France, involving CO2 monitors, scanners and sniffer dogs, had pushed the problem out to more “remote ports”.