Thirteen suspects arrested by French police over the deaths of 39 Vietnamese people found in a refrigerated lorry in Essex have been charged with people trafficking and manslaughter, a judicial source has said. Six of the group – mainly Vietnamese and French nationals – were taken into custody on Tuesday in the Paris region, while the alleged key figure in the ring of smugglers was caught in Germany. Thirteen people were also arrested in Belgium on the same day in an international police operation. The Vietnamese migrants – 31 men and eight women – were found dead in the lorry in an industrial zone in Grays, Essex, in October 2019. The driver of the lorry has already admitted manslaughter. Tuesday’s police swoop targeted the smugglers suspected of organising the migrants’ journey from Asia. The suspect arrested in Germany’s Upper Rhine region was a 29-year-old man nicknamed “the Bald Duke”, sources told Agence France-Presse. “He could be the head of the network on the French side,” a source close to the investigation said. The man’s nationality was not revealed. The 13 indicted in France were also charged with membership of a criminal organisation and all but one was remanded in custody. Eleven of the 13 suspects in Belgium have been charged by a judge in Bruges with people trafficking, membership of a criminal organisation and fraud, according to Belgian prosecutors. The investigation found that the migrants who died were loaded into the truck in northern France, and that the network continued to operate even after the tragedy, charging up to €20,000 (£18,000) to cross from France to the UK. Investigation sources told AFP the group caught in France was believed to have housed the migrants and sent them from Paris to the north by taxi. The driver of the lorry, Maurice Robinson, from Northern Ireland, last month pleaded guilty to 39 counts of manslaughter. Four other men are on trial in London over the tragedy, while another man, Ronan Hughes, is facing extradition from Ireland to the UK on 39 counts of manslaughter and one of conspiracy to commit unlawful immigration.