Up to 24 families have reported members of their family missing after bodies were discovered in the back of a lorry.

Police have taken forensic samples from people in central Vietnam who believe their family members might have been among the 39 found dead in a container truck in England last week.

Up to 24 Vietnamese families had reported to local authorities that their family members were missing, as of Sunday afternoon, the VNExpress news website reported.

Police took hair, fingernail and other forensic samples from people in Nghe An province to try and help identify the suspected trafficking victims who were found on Wednesday in the refrigerated container in an industrial park in southeastern England.

Thirteen people in Nghe An’s Yen Thanh district have been reported missing, with relatives fearing they were on the truck, which had arrived in the UK from the Belgian port of Zeebrugge.

At their home in the district’s Tho Thanh village, the mother and a brother of Vo Ngoc Nam were awaiting news from the UK after not hearing from him for a week.

“We suspect that he was in the container in which people died. We don’t know what’s going on, but we think it’s true,” Nam’s older brother Vo Ngoc Chuyen said.

In Do Thanh, another village in the district, people attended a Sunday Mass to pray for the missing.

Three families in Do Thanh have told local authorities their missing family members could be among the victims.

During the Mass, the priest, the Reverend Nguyen Duc Vinh, encouraged people to keep up their hopes.

UK police said on Saturday that all 39 victims were out of the truck and in a mortuary awaiting autopsies.

But they said the victims have not been identified and very few documents were found with the bodies.

Meanwhile, British police released three people on bail on Sunday after questioning them over the deaths.

A 38-year-old man, a 38-year-old woman – both from the northern English town of Warrington – and a 46-year-old man from Northern Ireland were questioned on suspicion of manslaughter and conspiracy to traffic people.

Residents of Vietnam’s Nghe An province hold a mass prayer on Saturday for the 39 people in died in the UK [Kham [Reuters]

Essex Police on Saturday charged the driver of the lorry, 25-year-old Maurice Robinson from Northern Ireland, with 39 counts of manslaughter, conspiracy to traffic people, conspiracy to assist unlawful immigration and money laundering. He will appear in court on Monday.

Irish police said another man was arrested on Saturday in connection with the case.

British police said their investigation included more than 500 exhibits, including cellphones that needed to be downloaded but could help identify the victims.

“We are working hard to understand how the 39 victims of this tragic incident have died and to identify all those involved,” said Detective Chief Inspector Martin Pasmore.

“We remain open-minded as to nationalities of those who have died. We are asking anyone who may have information that may assist us in identification to come forward.”