The 36-year-old man, whose name has not been disclosed, from Essex County, where the truck was found, remains in custody on suspicion of "conspiracy to traffic people and conspiracy to assist unlawful immigration," police said.

This is the seventh suspect arrested as British police continue to investigate the deaths of 39 Vietnamese citizens.

U.K. emergency services discovered their bodies, eight women and 31 men, in the refrigerated container truck at the Waterglade Industrial Park in Grays, Essex County, east of London, on October 23. The youngest victims were 15 years old and the oldest was 44.

Among the other six arrested is the 25-year-old truck driver Maurice Robinson, 25, of Northern Ireland. In a trial Monday, he pleaded guilty to assisting illegal immigration, but did not admit to 39 counts of manslaughter he has been charged with.

The defendant has been remanded to custody until a further hearing on December 13.

Another suspect Christopher Kennedy, 23, who was arrested last Friday and charged with human trafficking, appeared in court Monday but was not asked to enter pleas. He was also remanded to custody and will appear in court again on December 13.

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 involvement in human trafficking. 31 of the victims came from the two provinces.

The bodies of the 39 victims are still in the U.K. Vietnam is discussing with U.K. authorities the technical issues in the transferring of their remains.

The Vietnamese 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 and $2,855 for the bodies to be brought back in coffins.

Most families want the bodies of loved ones repatriated, and a few have opted for ashes.