GRAYS, England (Reuters) - British police want help from the Vietnamese community in Britain and abroad to identify the 39 people found dead in the back of a refrigerated truck on Wednesday, a senior officer said on Saturday.

Detective Chief Inspector Martin Pasmore said his officers had found “very, very few ID papers” among the bodies and hoped to identify the dead through fingerprints, dental records and DNA, as well as photos from friends and relatives.

Police initially said they thought the victims might be Chinese, but have since said they do not want to speculate on the victims’ nationality before they have been formally identified.

“We don’t know exactly the nationality of our individuals. But at the moment I am going to focus and engage as much as I possibly can within the Vietnamese community,” Pasmore said.

People from a rural region in central Vietnam have said they fear friends and relatives seeking to move to Britain make up a large number of the dead, who were found in an industrial park around 20 miles east of London.

The truck driver, a 25-year-old man from Northern Ireland, has been arrested on suspicion of murder, and three others are being held on suspicion of human trafficking and manslaughter.

Irish police on Saturday said they had arrested a fifth person in connection with the investigation.

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Pasmore, who is in charge of identifying the bodies but not running the criminal investigation, said his colleagues were keeping an open mind about whether the dead were victims of a wider human trafficking conspiracy.

“Criminals and murderers are taking more and more chances with these vulnerable people,” he said.

Pasmore said he had spoken with Vietnam’s ambassador to Britain to seek assistance with fingerprint records.

Pasmore said he had also contacted the operator of a Vietnamese community website and hoped Vietnamese people in Britain would “take a leap of faith” and help police identify friends and relatives, even if they were in Britain illegally.