A man from Northern Ireland has been arrested in connection with the deaths of 39 people found in the back of a lorry in Essex.
The bodies were found in a refrigerated container in Thurrock on October 23 this year.
The 23-year-old Northern Ireland man was detained in the early hours of Friday on the M40 in Beaconsfield, Buckinghamshire.
Essex Police said he would be questioned on suspicion of conspiracy to traffic people and conspiracy to assist unlawful immigration.
The people found dead, who were from Vietnam, were eight women and 31 men. Ten teenagers, including two 15-year-old boys, were among the victims.
Lorry driver Maurice ‘Mo’ Robinson, 25, has been charged with 39 counts of manslaughter.
Three other people who were arrested on suspicion of manslaughter and conspiracy to traffic people have been released on bail.
Police also started the extradition of a Co Down lorry driver at the High Court in Dublin.
Essex Police is seeking the extradition of Eamonn Harrison, 22, a truck driver from Mayobridge, who is being held in the Republic of Ireland.
He appeared at Dublin’s Central Criminal Court on 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.
The court heard that the UK authorities say Mr Harrison drove the truck with the refrigerated container to Zeebrugge in Belgium before it was collected in Essex by Craigavon driver Maurice Robinson.
Robinson, 25, of Laurel Drive, Craigavon, appeared in court in Chelmsford on 28 October.
He will next appear at the Old Bailey in London on Monday, November 25