(CNN) The 39 people found dead in the back in the back of a truck in England last month are believed to be Vietnamese nationals, Essex Police said in a statement Friday.

"At this time, we believe the victims are Vietnamese nationals, and we are in contact with the Vietnamese Government," Assistant Chief Constable Tim Smith said in the statement.

He added that police were in "direct contact with a number of families in Vietnam and the UK, and we believe we have identified families for some of the victims whose journey ended in tragedy on our shores."

The development comes a week after 39 people were found dead in the back of a refrigerated lorry in a UK industrial park in Grays, Essex, 20 miles east of London.

Essex Police initially believed that the people found dead were Chinese nationals "based on the documentation found on them," a press officer told CNN.

39 dead bodies were found in a truck in Essex, southeast England.

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