A BBC documentary on the shocking discovery of the bodies of 39 Vietnamese migrants in an Essex lorry park is airing on Wednesday.
Hunting the Essex Lorry Killers will uncover how detectives cracked open an international smuggling ring after the migrants' bodies were found in Grays in October 2019.
A subsequent investigation into the deaths was the biggest in Essex Police's history.
The show will speak to Essex Police officers who painstakingly pieced together evidence to bring down a gang of people-smugglers.
The film also travels to Vietnam to meet the families of some of those who died in the back of the lorry.
Eight people have been convicted of crimes related to the incident so far.
The documentary will broadcast at 9pm on BBC Two.
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