Essex Police, which is investigating last week’s grim discovery, said they wanted to speak to Ronan Hughes, 40, and his 34-year-old brother Christopher, who are both from Armagh.
Eight women and 31 men were found last Wednesday (Oct 23) in a refrigeration truck trailer that entered Britain on a ferry from Belgium. Several Vietnamese families fear their relatives are among the dead.
“Finding and speaking to the Hughes brothers is crucial to our investigation,” said Detective Chief Superintendent Stuart Hooper.
“We believe they are in Northern Ireland but they also have links to the Irish Republic.
“Thirty-nine men and women have tragically died and support from the community is going to be vital to help bring those responsible to justice.”
Ambulance crews called to the scene in Grays, just over an hour after the trailer arrived at the nearby port of Purfleet, said all those inside were already dead.
The truck driver, 25-year-old Maurice Robinson from Northern Ireland, has been charged with 39 counts of manslaughter, conspiracy to traffic people, conspiracy to assist unlawful immigration, and money laundering.
He appeared in an Essex court via video-link on Monday and was remanded in custody to appear next at the Old Bailey in London, England's central criminal court, on November 25.
Three other people arrested in connection with the investigation – a 38-year-old man, a 38 year-old-woman, and a 46-year-old man – have all been released on bail until November.
The bodies of all of the victims have been moved to a hospital for post-mortem examinations.
It is not yet known when the victims entered the trailer or the exact route it travelled.
AFP has spoken to several families of missing Vietnamese nationals – ranging from 15 to 37 years old – feared to be among the dead.
DNA has been collected from relatives as officials in Vietnam and Britain attempt to identify the victims.