A documentary following the case of the Essex lorry killers is set to air this week on BBC Two.

Hunting the Essex Lorry Killers follows the October 2019 incident where 39 Vietnamese migrants were found dead in the trailer of a lorry in Grays.

The documentary will show how detectives cracked open a multi-million-pound international smuggling ring, with its roots in a seemingly innocuous haulage business in the heart of Northern Ireland.

Filmmakers also travelled to Vietnam to meet the families of some of those who died in the back of that lorry, to hear the stories of losing loved ones on the false promise of a new life in the UK.

It will air on Wednesday 13 October at 9pm on BBC Two and will be available on the BBC iPlayer shortly afterwards.

Thurrock Gazette: DC Martin Brown was part of the investigation (BBC/Expectation Entertainment)DC Martin Brown was part of the investigation (BBC/Expectation Entertainment)

But what is the full story behind the tragic incident?

What is the full story behind Hunting the Essex Lorry Killers?

The full incident was as a result of a smuggling ring based in Northern Ireland.

Ronan Hughes and Gheorghe Nica were charged with being the ringleaders of the operation in the legal proceedings following the truck being found.

The truck had made its way from Zeebruge in Belgium on a freight ferry to the town of Purfleet.

GPS has shown it had visited Dunkirk and Lille in France and Bruges in Belgium beforehand.

Hughes and Nica had arranged for a local Essex man, Mo Robinson, to collect a container filled with the Vietnamese people.

He collected it from Purfleet before stopping at Grays.

On opening the doors on October 23, 2019, he discovered they were all dead.

It was later confirmed by Essex Police that the deaths were as a result of a combination of hypoxia and hyperthermia, as the refridgerated truck they were in could be kept airtight.

After waiting 20 minutes Robinson phoned emergency services, eventually leading to his arrest and sentencing to 13 years in jail.

Later Hughes and Nica were sentenced to 27 and 20 years retrospectively in prison.

Eamonn Harrison, who delivered the trailer to Zeebrugge was sentenced to 18 years