The 23-year-old man, whose name has not been disclosed, remains in custody on suspicion of "conspiracy to traffic people and conspiracy to assist unlawful immigration," police in Essex, where the truck was found, said in a statement.
The latest arrest, sixth in the ongoing investigation, comes a month after U.K. emergency services discovered the bodies of 39 people in a refrigerated container truck at the Waterglade Industrial Park in Grays, Essex County, east of London.
Among the other five arrested is the 25-year-old truck driver Maurice Robinson, who faces charges of 39 counts of manslaughter and other offenses, including conspiracy to traffic people.
In Vietnam, police have arrested 11 people, nine in the central province of Nghe An, and two others in neighboring Ha Tinh Province, for suspected involvement in human trafficking.
Earlier this month, authorities released the identities of all 39 Vietnamese killed in the truck disaster. The youngest victims were 15 years old and the oldest was 44.
Nghe An was home to the majority of the victims, losing 21, followed by Ha Tinh with 10. Others came from Hai Phong and Hai Duong in northern Vietnam, and the central provinces of Quang Binh and Thua Thien-Hue.
As of now, there has been no information on when the victims’ bodies will return to Vietnam.
Deputy Foreign Minister Bui Thanh Son said Thursday the government has decided to make advance payments to make sure the victims are brought home as soon as possible. It will cost $1,771 to receive the victim’s ashes or $2,855 for the bodies to be brought back in coffins.