Pictures: The discovery of 39 bodies in a lorry container in Essex
A 25-year-old-man from Northern Ireland has been arrested on suspicion of murder after 39 people were pronounced dead at the scene in Grays, Essex.
Early indications suggest 38 are adults and one aged in their teens, police said.
Essex Police said it was called by the ambulance service shortly before 1.40am on Wednesday following the discovery of a lorry container with people inside at Waterglade Industrial Park, Grays
Chief Superintendent Andrew Mariner said: "This is a tragic incident where a large number of people have lost their lives. Our enquiries are ongoing to establish what has happened.
"We are in the process of identifying the victims, however I anticipate that this could be a lengthy process."
"We believe the lorry is from Bulgaria and entered the country at Holyhead on Saturday 19 October and we are working closely with our partners to investigate."