Dozens of people have been arrested, including an oil heiress and singer who was found with €300,000 (£260,000) in cash when her Rolls-Royce was pulled over in 2019, as Italian police disrupted a massive fuel fraud by mafia groups. Police also seized nearly €1bn in assets linked to mafia money laundering and tax fraud through oil products in a series of scams known as “Operation PetrolMafias”. Allegedly carried out by different clans within the Naples’ Camorra and Calabrian ’Ndrangheta syndicates, the various schemes underscored the “nefarious synergy between mafias and white-collar criminals”, prosecutors said in a statement. More than €173m has been laundered in various oil-related schemes investigated by police since 2015, said prosecutors in Naples, Rome, and two provinces of Calabria at the tip of Italy’s boot, where the ’Ndrangheta crime organisation is firmly entrenched. More than 1,000 police officers participated in the operation early on Thursday, seizing property, businesses and cash worth nearly €1bn. The probe uncovered “the gigantic convergence” of different mafia groups that came together to illegally import and market fuel products while laundering proceeds via front men and shell companies. Through fraudulently mislabelling imports or transports of petroleum products, suspects were able to avoid taxes, while a series of paper companies issuing fake payments for nonexistent supplies allowed the clans to launder money from their illegal activities. In one ’Ndrangheta diesel fuel scheme involving 12 companies, five fuel depots and 37 gas stations, fuel that had evaded excise and value-added tax was put on the market. In one year alone, from 2018 to 2019, suspects evaded paying €5.8m in excise tax. In Naples and Rome, police targeted the Moccia clan, described as one of Italy’s “most powerful and dangerous” groups within the Naples-based Camorra crime syndicate. The clan is skilled at liaising with leading public and private sector figures to help invest illegally gained proceeds in the legal economy, prosecutors said. In another scheme, the clan allegedly teamed with a former singer and widow of an oil entrepreneur, Anna Bettozzi, whose inherited business was struggling. Laundered cash injections from the Camorra and shell companies supplying fake invoices helped grow her oil business from €9m to €370m in three years, prosecutors said. Bettozzi, among those arrested on Thursday, was found with €300,000 in cash when she was stopped in 2019 in a Rolls-Royce on her way to the Cannes film festival, they said. Another €1.4m in cash was later seized from her Milan hotel. The investigation into the oil fraud schemes of the ’Ndrangheta groups is related to a massive operation against the mafia group in December 2019 that resulted in the arrest of more than 300 people. Most of those apprehended in the biggest police operation in years against clans in Calabria’s Vibo Valentia area now face judges in a “maxi-trial” to answer for crimes including murder, drug trafficking, extortion, money laundering and abuse of office.