©Bloomberg

Police have raided the offices of Gerdau, Brazil’s largest steelmaker, and issued an arrest warrant for its chief executive as part of an inquiry into a nationwide kickback and bribery scheme at the country’s tax agency.

The federal police said on Thursday that they suspected the company of evading R$1.5bn ($379m) in back taxes through the scheme, which has emerged alongside a separate corruption scandal at state oil company Petrobras.

In the sixth phase of the tax investigation — termed “Operation Zealots” — police said they had issued 22 arrest warrants and 18 search and seizure warrants at Gerdau’s offices across five Brazilian states.

Police said one of the executives to be summoned to testify was André Gerdau Johannpeter, head of the Gerdau family empire whose father is one of President Dilma Rousseff’s closest advisers. Local media said he would appear voluntarily later on Thursday.

Gerdau, Brazil’s largest steelmaker by volumes, said in a statement that police had been at its offices on Thursday morning, adding that it would co-operate fully with the federal police’s investigations and denying any illegal behaviour. Its shares fell 4.8 per cent on Thursday. Mr Gerdau Johannpeter could not be reached for comment.

Just as Brazil’s authorities were investigating a vast kickback and bribery scheme at Petrobras last year, police reported another corruption scheme involving the country’s board of tax appeals.

Police say they suspect companies bribed members of the Carf, the part of Brazil’s finance ministry responsible for ruling on tax appeals, to get favourable decisions that reduced or waived the sums owed.

When the scheme was first uncovered in March last year, police said they would investigate at least 70 industrial, engineering, agricultural and financial groups over possible bribes to tax officials.

Over the past few years, Brazil’s crusading public prosecutors have grown increasingly active, taking advantage of the independence afforded to them by Brazil’s 1988 constitution to investigate the country’s most powerful figures.

Among those who have been arrested so far in connection with the Petrobras scandal include André Esteves, one of the country’s top bankers, and Marcelo Odebrecht, head of Brazil’s largest engineering conglomerate.

Mr Esteves, who was later released on house arrest, and Mr Odebrecht, who remains in jail, have both denied wrongdoing.

On Tuesday, João Santana, the manager of Ms Rousseff’s 2010 and 2014 presidential campaigns, was also arrested by police over allegations he took bribes as part of the Petrobras scheme. Mr Santana has labelled the accusations as “baseless”.