Dec. 5 (UPI) -- Brazilian police said Wednesday it's investigating up to $31 billion in alleged bribes to officials of state oil company Petrobras by some of the largest multinational oil traders, and has arrested 11 people.
Among the companies named are Vitol, Trafigura, Glencore, Chemium and Oil Trade and Transport, Folha de Sao Paulo reported Wednesday.
The names of the arrested include representatives of Trafigura in Brazil, as well as Petrobras officials in Houston, Folha's report said.
"They are giants in the market of trading and commodities commercialization," delegate Filipe Pace told the newspaper.
The alleged bribing would have occurred between 2011 and 2014, according to the report.
Just three multinationals, Vitol, Trafigura and Glencore are suspected of paying $15 million during those years to win favor in oil trading or leasing fuel tanks, Folha reported.
A Petrobras official told Folha the company is cooperating with authorities and has been recognized as a "victim" of the crimes by judicial authorities. Petrobras is the "most interested" party in the investigations, the company said.
A Trafigura spokesperson told UPI company officials "do not comment on legal matters."
Separately, Vitol told UPI the company "has a zero tolerance policy in respect of bribery and corruption" and will always cooperate with authorities in any jurisdiction in which it operates.
The other companies named did not immediately reply to other requests by UPI.
The scheme allegedly included variations so that prices were increased by as little as 1 cent per barrel,. But given the large volumes, it added up to several millions, investigators say.
The website of the Brazilian federal police reported the information of the investigation, but had not published names of the companies involved or of the people detained.
Police said they're executing 27 searches, in addition to blocking assets of the suspects.