Brazilian police raided offices and arrested former senior company officials over an alleged R$40m ($10.3m) wind power fraud as an operation code-named 'Gone With the Wind' probes some of the biggest players in the nation’s renewable energy sector.

The police operation centres on alleged fraudulent overpricing and subsequent corrupt payments and money laundering arising from the 2014 sale of the 676MW Zeus wind project by Casa dos Ventos to fellow developer Renova.

Gone With the Wind is an offshoot of Brazil’s massive ‘Car Wash’ corruption probe, which has spent years investigating fraud and corruption at all levels of the Brazilian economy, principally in finance and construction. Its highest-profile moment came with the arrest of former President Luis Inácio Lula da Silva, and it has revealed massive corruption involving Brazil’s largest construction and industrial conglomerate, Odebrecht, which also has interests in renewable energy.

Investigators claim Renova and Casa dos Ventos initially agreed a R$105m sale price, but this was later bumped up to R$145m. The extra cash allegedly later found its way into other hands in exchange for non-existent services in areas such as printing, brokering fees, publicity and construction contracts.

In total, five arrest warrants and 26 warrants for seizure of computers, cell phones and documents were issued. Those arrested include one of Renova’s founders Renato do Amaral, while phone records of former CEO Mathias Becker and CFO Pedro Pilleggi were also examined.

“When the date of payment of transaction was drawing near, the founder of Renova and his main executive officer sought out the founder of Casa dos Ventos … and proposed a R$40m overprice. Then they suggested transferring this money to people we’ll name,” said public prosecutor Victor Hugo Rodrigo Alves.

Gone With the Wind is also investigating the role of officials at Cemig – the state-controlled power group that was a major shareholder in Renova and owned 50% of Zeus, and was supposed to take power from the wind farm – and construction firm Andrade Gutierrez, which was an early shareholder in Renova.

Plans to advance Zeus were scrapped in 2017 as a result of financial difficulties faced by Renova and Cemig and the wind farm has never been built.

The arrests were made last week to prevent suspects from leaving the country or destroying evidence, but no charges have yet been laid.

Renova issued a statement saying that the events cited occurred under previous corporate administrations and that it will co-operate with the investigations. Casa dos Ventos stressed that its executives were not being directly investigated, but said it will co-operate with public prosecutors and the police.

The corruption accusations against Renova come soon after it closed a R$516m deal to sell its 743MW Alto Sertão III project to a local unit of US energy group AES.