Two Brazilian offices of Cisco Systems were raided by police last week and several staff detained in a widespread crack-down on tax evasion in the country.

Brazilian authorities are seeking co-operation from the US government to arrest five further executives who they believe masterminded the scheme. Cisco has confirmed they are helping the police with its investigation.

Local press reports suggest over 40 people were arrested in the raids, carried out at a number of locations. Brazilian authorities confirmed a number of senior executives have been detained as part of the investigation.

The raids are part of Operation Persona, a two-year investigation of a smuggling ring that the Brazilian authorities believe involves Cisco employees. It is alleged that the vendor's Brazilian operation has not paid import tax on equipment worth over $500m during the last five years.

Cisco released an official statement which read: "Numerous raids were conducted [Wednesday] in Brazil in connection with an alleged scheme to evade payment of taxes. Brazilian authorities visited and temporarily closed Cisco's offices in Sao Paulo and Rio de Janiero. We understand that a small number of employees have been detained."

The statement continued: "We are currently in the process of establishing what exactly has happened in Brazil and determining how this investigation pertains to Cisco. We are co-operating fully with the Brazilian authorities."

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