Belgian police have confirmed that they have retrieved CCTV footage of the lorry and driver, that dropped a container carrying immigrants on a ferry, bound for the UK.
22 adults and 13 children, aged between 1 and 12, were discovered in the shipping container when it arrived from Belgium at Tilbury Docks, in Essex, after "banging and screaming" was heard from inside.
One man, in his 40's, was found dead. The others were taken to hospital suffering from severe dehydration and hypothermia.
Peter De Waele, a spokesman for Belgium's federal police, told Sky News that detectives were checking "every image" of CCTV from Zeebrugge port.
"We have a lot of cameras and we are very hopeful for having information about identification of the driver. When you know that in this area there are a lot of cameras, you know also that we have plenty of information about the truck and the driver, and the firm who put the container in Zeebrugge."
It has been revealed that the people were Afghan Sikhs and may have been victims of human trafficking.
The group were found at 7.35am on Saturday (16 August) when the Norsteam, a commercial ship run by P&O Ferries, was being unloaded in Tilbury.
Natalie Hardy, a company spokeswoman, said the ship had travelled overnight from Belgium and was carrying 64 containers, 72 trailers and five lorries and drivers.
The moment the immigrants were released from the container was captured by a witness on his mobile phone.
In the video, women can be heard crying and screaming, while young children are clearly distressed following their ordeal.
Thirty of the victims have been discharged from hospital while four are still receiving medical treatment.
Superintendent Trevor Roe, of Essex Police, said: "The welfare and health of the people is our priority at this stage. Now they are well enough, our officers and colleagues from the Border Force will be speaking to them via interpreters so we can piece together what happened and how they came to be in the container."
Inspector Roe said police have received support from the local community and the Red Cross.
"We have had a good deal of help from partners within the local Sikh community in the Tilbury area to ensure that these poor people, who would have been through a horrific ordeal, are supported in terms of their religious and clothing needs."
Interpol and other international forces are helping Essex Police trace the lorry's route across Europe in an effort to track down the suspected traffickers.
Essex Police have launched a "homicide" investigation after the death of the male immigrant and detectives said charges could include murder or manslaughter.
Information on the ages of the immigrants or the relationship between them has not yet been released.