A 36-year-old man from Purfleet has been arrested on suspicion of manslaughter in connection with the deaths of 39 Vietnamese people in a lorry in Grays, Essex Police said.
Police said he was arrested on Monday morning at a property in Dalston, east London.
He was also arrested on suspicion of conspiracy to traffic people and conspiracy to assist unlawful immigration. He remains in custody for questioning.
Eight females and 31 males were found in the trailer early on October 23 at an industrial park.
The people were identified as coming from various provinces of Vietnam, with the youngest being two boys aged 15. Emergency services were called to an industrial estate in Grays shortly after the lorry arrived on a ferry from Zeebrugge in Belgium.
On Monday, a lorry driver charged with manslaughter pleaded guilty to plotting to assist illegal immigration.
Maurice Robinson appeared at the Old Bailey in London via video link from Belmarsh prison for a plea hearing. He spoke to confirm his identity and British nationality.
He admitted conspiracy to assist unlawful immigration between 1 May 2018 and 24 October 2019.
Police in Vietnam have arrested eight people suspected of being part of a ring responsible for smuggling Vietnamese people to Britain.
Essex police have also launched extradition proceedings to bring 22-year-old Eamonn Harrison from Ireland to the UK. He appeared at Dublin’s central criminal court last Thursday after he was arrested on a European arrest warrant in respect of 39 counts of manslaughter, one count of a human trafficking offence and one count of assisting unlawful immigration.
Harrison is accused of driving the lorry with the refrigerated container to Zeebrugge in Belgium before it was collected in Essex by Robinson. Robinson was remanded in custody until a further hearing on 13 December.