Police have arrested a second man in connection with an investigation into the death of an immigrant found in a container at Tilbury Docks.
The 33-year-old from Londonderry was arrested shortly after 1pm today after voluntarily attending a police station in Essex, police said.
He has been arrested on suspicion of manslaughter and facilitating illegal entry into the United Kingdom in connection with the police investigation into the death of a man found in a container on Saturday.
Police said he will be questioned by detectives later today.
The man arrested in Northern Ireland yesterday is not due to arrive in Essex Police custody until late this evening, the force added.
Meet Singh Kapoor, 40, from Afghanistan, was found dead inside the container at Tilbury on Saturday.
Other members of the 34-strong group, including 13 children, survived the ordeal. They are all Afghan Sikhs from Kabul.
The group is believed to have fled Afghanistan after suffering persecution.
They are in the process of claiming asylum in the UK after travelling to Europe in a lorry before reportedly spending 18 hours in the cargo container en route to the UK.
A separate investigation is under way after a refrigerated lorry containing 15 people was discovered at a service station in Ilminster, near Taunton, by officers from Avon and Somerset Police working alongside immigration officials.
Almost 50 victims of human trafficking are discovered in the UK each week, Government figures have shown as the recent cases highlighted the issue of people smuggling.
Figures recorded by the National Crime Agency (NCA) show that 566 potential cases of trafficking were identified by police forces, local authorities, charities and Home Office officials across the UK in the first three months of this year.
According to an NCA report the most common reason for an adult being trafficked was sexual exploitation but there were also many cases of people being transported as cheap labour or into domestic servitude.
One case of a person being trafficked for organ harvesting was also detected during that period.
Last year 1,746 potential trafficking victims were found in the UK - an increase of 47% on the previous 12 months.
The Refugee Council, which works with people seeking asylum in the UK, said that it was difficult to establish the full scale of people smuggling into the UK after fleeing their home countries, as opposed to those who are trafficked for exploitation.
But the charity said the Tilbury incident was a "grim reminder" of the difficulties asylum seekers face.
Chief executive Maurice Wren said a lack of safe and legal routes for refugees meant they are often left with no choice other than the risk using the services of people smugglers.
He added: "This tragedy illustrates, all too painfully, the desperate measures that people who are in fear of persecution, yet have no-one to turn to for protection in their home countries, will take in search of safety."
A Home Office spokesman said officials would not comment on the figures because of the ongoing high-profile investigations.
The NCA figures covering January to March this year included 392 adults and 174 children, with the most common countries of origin being Albania, Slovakia, Nigeria and Vietnam.
This represents the equivalent of 47 possible trafficking victims each week.
Once victims are initially identified, they are assessed to establish whether they have been trafficked and why they were illegally transported.
A German lorry driver arrested after the 15 foreign nationals were found in the back of his truck has been released on bail.
The 50-year-old was held following the discovery of 11 men, three women and a 15-year-old boy in lorry at a service station in Somerset .
The discovery was made after police were alerted by a motorist to noises coming from the rear of the refrigerated lorry, owned by international freight company Thermotraffic.
When Avon and Somerset officers opened the doors of the HGV they discovered the group - who said they were from Eritrea and Kashmir - distressed and suffering from dehydration.
The lorry driver, who was arrested on suspicion of facilitating the unlawful entry of people into the UK, has been released on bail until November.
The foreign nationals are believed to have gained entry to the lorry at a European ferry port as the driver made his way to the West Country.