Ronan Hughes and Christopher Hughes are wanted by Essex Police for questioning
Essex Police said in a statement on Tuesday afternoon that they are now searching for two men from Co Armagh in relation to the 39 bodies discovered in the back of a lorry in England last week.
In the statement, Essex Police said that Ronan Hughes, 40, and his brother Christopher Hughes, 34, both from Co Armagh, "are wanted on suspicion of manslaughter and human trafficking.
“Ronan Hughes, who also goes by the name Rowan, and Christopher have links to both Northern Ireland and the Irish Republic."
Detective Chief Superintendent Stuart Hooper, who is leading the investigation, said: “Finding and speaking to the Hughes brothers is crucial to our investigation.
“At this time we believe they are in Northern Ireland but they also have links to the Irish Republic.
“If you know where they are or have any information about their whereabouts I need you to call my team."
Hooper added: "This is a case where 39 men and women have tragically died and support from the community is going to be vital to help bring those responsible to justice."
25-year-old Maurice 'Mo' Robinson, also from Co Armagh, was charged on Saturday with 39 counts of manslaughter, conspiracy to traffic people, conspiracy to assist unlawful immigration, and money laundering.
He was understood to be driving the tractor where the 39 bodies were discovered in the early hours of October 23. He's the only person to be formally charged so far and is due to appear at the Old Bailey on November 25.
Three other people were arrested last week – a 38-year-old man, a 38-year-old woman, and a 46-year-old man – but have all been released on bail until November.
On Friday, Essex Police commenced post-mortem examinations and formal identifications of the 39 victims. The police force has yet to publicly confirm the nationalities of those who died.