Christopher Kennedy, 23, of Northern Ireland was arrested on Friday and is due to appear in court on Monday, Essex police said in a statement.

The latest arrest, sixth in the ongoing investigation, comes a month after U.K. emergency services discovered the bodies of 31 men and eight women in a refrigerated container truck at the Waterglade Industrial Park in Grays, east of London.

Among those arrested is the truck driver, Maurice Robinson, also of Northern Ireland, who has been charged with 39 counts of manslaughter, conspiracy to traffic people and money laundering.

Robinson is also due to appear in court, for the second time, on Monday.

In Vietnam, police have arrested 11 people, nine in the central province of Nghe An and the two others in neighboring Ha Tinh Province, for suspected human trafficking.

Earlier this month authorities released the identities of the victims. The youngest victims were 15 years old and the oldest was 44.

Nghe An was home to the majority of them, 21, followed by Ha Tinh with 10. The rest were from Hai Phong City and Hai Duong Province in northern Vietnam and the central provinces of Quang Binh and Thua Thien-Hue.

It is not known yet when the victims' bodies will be repatriated to Vietnam.

Deputy Foreign Minister Bui Thanh Son said on Thursday the government has decided to make advance payments to make sure the victims are brought home as soon as possible. It will cost $2,855 for the bodies to be brought back in coffins and $1,771 for their ashes.