Two thousand employees of Brazil's state-run oil giant Petrobras are now under investigation in a corruption scandal that has rocked the country for months.

An internal audit led by former Minister of the Federal Supreme Court, Ellen Gracie seized the computers and mobile phones of more than 2,000 employees with access to information regarding projects examined by the federal police's "Lava Jato Operation" (Portuguese for "Operation car wash").

"Men in suits came out of nowhere to get computers and mobile phones. Without notice. No one knew who they were," an employee who occupies a top position at Petrobras headquarters told Zero Hora.

Information saved locally on the mobile phones and computers will help the inquiry work out the scale of the corruption and pinpoint people involved.

Maria das Graças Foster, the CEO of Petroleo Brasileiro (Petrobras) and five members of the state-run oil giant's board of directors, were forced to resign last week following revelations that the company lost up to $33bn (£21.6bn) in 2014 due to corruption and financial inefficiency.

The board of Petrobras named Brazil's former central bank chief executive officer Aldemir Bendine as its new chief executive last week.

Investigations into the corruption have also focused on President Dilma Rousseff and her Workers' Party, where a senior official was questioned.

Overall, more than 232 companies, including some of Brazil's largest construction and engineering firms have been, or are being investigated.

Some 150 executives and Petrobras directors have also been under investigation. So far, around 80 people have been charged with corruption, according to local officials.

Gracie was appointed by Petrobras in December last year to carry out investigations.