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.

Israeli airforce pounds Beirut, Lebanon death toll rises
US releases Epstein-related FBI interviews mentioning Trump
Hezbollah warns Israeli residents to evacuate towns near border
US House rejects war powers resolution, backs Trump on Iran war
Saudi Arabia, Qatar, Kuwait intercept drones targeting territory
GCC and EU ministers urge immediate halt to Iranian attacks
India's tech state Karnataka bans social media for children under 16
Indonesia says it will withdraw from Board of Peace if it does not benefit Palestinians
