Essex Police said it was "very grateful" to the Police Service of Northern Ireland (PSNI) for its assistance in arresting a man in connection with the death of an Afghan immigrant aboard a shipping container found at Tilbury docks.
This is a fast-moving investigation which has already involved a number of police forces and law enforcement agencies from across the United Kingdom and Europe.
"We will continue to work closely with all of our policing colleagues as we pursue our investigation to bring those responsible for this crime to justice.
It is thought the 35 people found at Tilbury docks had travelled by lorry from Afghanistan before spending 18 hours inside the container as it travelled from Zeebrugge, Belgium.
The uncle of dead Afghan immigrant Meet Singh Kapoor says he wanted a better life for his children. Instead his children watched him die.
ITV News has spoken to the translator police used after 35 Afghan Sikhs, including 13 children, were found in a boat in Tilbury Docks.
ITV News has obtained exclusive footage of people, believed to be Afghan Sikhs, being released from a shipping container at Tilbury Docks.