Two brothers have been desired over 39 people on suspicion of manslaughter.
Ronan Hughes, 34, and Christopher Hughes, 40, from Armagh in Northern Ireland, are wanted by authorities on suspicion of trafficking.
The 39 bodies have been found on Wednesday from the trailer on a property in Grays.
The driver of the lorry, Maurice Robinson appeared in court on Monday such as 39 counts of manslaughter.
Det Ch Supt Stuart Hooper stated: “Finding and talking to the Hughes brothers is vital to our evaluation.
“This really is a situation where 39 women and men have died and support in the community will be crucial to help bring those responsible to justice”
Essex Police said Ronan Hughes requested regarding their whereabouts and goes by the title Rowan.
Three individuals – a girl, a guy, along with a guy – have been released on bond.
Another motorist, who’s suspected of bringing the container until it crossed the Channel, into Zeebrugge, was detained on charges that were unrelated on Saturday at the port of Dublin.
But authorities, that are currently liaising with their Essex counterparts,” said the guy was the driver of a truck captured in Dublin port to the 39 deaths as part of their investigations.
Police had originally thought that the 31 men and eight girls discovered dead at the container in the wee hours of Wednesday morning were Chinese.
However, a number of households have come fearing their nearest and dearest are among the deceased.
The BBC knows that officers from provincial and federal authorities departments are all set to go to help with the question.
Authorities have taken DNA samples in a few of the relatives of victims to aid with the identification process’ fingernails and hair.
News agency Reuters said records pertaining to authorities to four of those deceased have been sent by authorities.
It noted that Vietnam’s deputy foreign minister Nguyen Quoc Cuong explained his nation and Britain were”attempting to hasten the identification of their bodies, but no deadline was set”.