The PSNI have raided a suspected fuel laundering plant at Coalisland in an operation linked to the investigation into the death of a man in a container in Essex.
The dead man was one of 35 people from Afghanistan, including 15 children, found at Tilbury Docks on 16 August.
Three people have now been arrested on suspicion of manslaughter.
In follow-up searches, police have found a suspected fuel laundering plant and 1350 litres of fuel in Coalisland.
The facility, which was said to have been capable of producing 1000 of illicit fuel per day, has been dismantled.
Police said a 47-year-old man from Dungannon was arrested earlier at Liverpool Ferry Port by port police.
He is due to be transferred into the custody of Essex Police.
Two other men also charged in connection with the death remain in custody to appear at Basildon Crown Court in November.