A 36-year-old man has been arrested on suspicion of manslaughter in connection with the deaths of 39 Vietnamese people in a lorry in Grays, Essex.
Police said the man, from Purfleet in Essex, remains in custody.
The arrest is the latest to result from the investigation into how 31 men and eight women came to die in the back of a refrigerated lorry and left in an industrial estate.
Ten teenagers, including two 15-year-old boys, were among the bodies of 39 Vietnamese nationals discovered in the early hours of October 23, shortly after the lorry arrived on a ferry from Zeebrugge in Belgium.
39 Bodies found in a container at Waterglade Industrial Park, Grays
Maurice Robinson, known as Mo, was the first to be arrested after the shocking discovery.
The 25-year-old was charged with the manslaughter of all those on board the lorry as well as with allegations of people trafficking, breaking immigration laws and money laundering.
At the Old Bailey on Monday, Robinson admitted being part of an international smuggling ring.
His charges related to a 17-month conspiracy running between May 2018 and October 24 this year.
The truck driver, who is British, pleaded guilty to conspiring with two other men and “other persons unknown” to break the British immigration laws, according to the charge sheet.
A previous hearing was told police are probing a “global ring facilitating movement of a large number of illegal immigrants into the UK”.
Another man from Northern Ireland was charged with human trafficking offences last week.
Christopher Kennedy, 23, was arrested in the early hours of Friday morning on the M40.
Kennedy, from Darkley, Co Armagh, has been charged with conspiracy to arrange or facilitate the travel of people with a view to exploitation and conspiracy to facilitate the commission of a breach of UK immigration law.
He appeared in Chelmsford Magistrates' Court on Monday and spoke only to give his name, age, address and nationality.
Extradition proceedings have also been launched in Ireland to bring Eamonn Harrison, 22, from Mayobridge in Newry, Co Down, to the UK.
Detectives have also urged Ronan Hughes, 40, and his brother Christopher, 34, from Armagh, Northern Ireland, to hand themselves in. They are wanted on suspicion of manslaughter and human trafficking.
