Police investigating the deaths of 39 people found in a lorry container in Essex have arrested a fourth person at Stansted Airport.
The 48-year-old man was detained on Friday on suspicion of conspiracy to traffic people and manslaughter.
Earlier, police said they had arrested a 38-year-old man and a 38-year-old woman from Warrington, Cheshire, on the same counts.
The driver of the lorry was arrested on suspicion of murder at the scene of the discovery in Grays in the early hours of Wednesday.
Police are yet to name or charge any of the suspects, but Sky sources identified the driver as Mo Robinson, 25, from the town of Portadown in County Armagh, Northern Ireland.
The 39 victims were found in a refrigerated trailer at Waterglade Industrial Park early on Wednesday and 11 of the bodies have now been taken to a mortuary at Broomsfield Hospital in Chelmsford for post-mortem examinations.
All of the bodies are expected to be moved by the end of the week.
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Following the discovery of the victims in an industrial estate, Essex Police initially said they believed the deceased were Chinese nationals but have now said it is a "developing picture".
Deputy Chief Constable Pippa Mills said she would not be drawn on any further details about the victims' nationality until formal identification processes had taken place.
She said: "I strongly urge journalists and people on social media not to speculate about the identities of those involved or the circumstances surrounding this investigation.
"We gave an initial steer on Thursday on nationality, however this is now a developing picture."
A Vietnamese woman is feared to be among the dead. Tra My was named as a possible victim by a member of a Hanoi-based human rights group.
The 26-year-old, who was identified on Twitter by Human Rights Space coordinator Hoa Nghiem, sent a series of haunting messages to her family at around the time the container was in Essex.
Sky News has translated the texts, which say: "So sorry mum and dad. The route to abroad didn't succeed. Mum. I love you and dad so much. I am dying because I can't breathe. I am from Can Loc Ha Tinh. Vietnam. Mum. I'm very sorry."
The lorry cab Mr Robinson was driving started its journey in Northern Ireland, from where it headed to Dublin and then caught a ferry to Holyhead in north Wales, before meeting the trailer in Purfleet not long after midnight, early on Wednesday.
Belgian authorities believe the container went to the UK from Read More – Source