The 39 people found dead in the back of a lorry in Essex were all Chinese nationals, it has been reported.
Police have searched two addresses in Northern Ireland connected to the driver - 25-year-old Mo Robinson from Northern Ireland, as the National Crime Agency works towards identifying "organised crime groups who may have played a part".
He remains in custody for questioning on "suspicion of murder".
It comes as Belgian authorities continue to investigate the journey of the lorry where the bodies were found.
13 killed in explosion at Qatar's Ras Laffan LNG site
UK PM Starmer says he will resign
Fire at coaching centre in India's Lucknow kills at least 15
Temperatures to exceed 40C in European heatwave as three die in France
US, Iran conclude high-level talks in Switzerland, mediators say
