Rome, December 11 - A petrol bomb that was put out at a branch of Italy's biggest bank, Unicredit, was planted there by an employee for unknown reasons, police said Tuesday. Investigators said the woman confessed to putting it there earlier Tuesday, inside the premises of the highest court of appeals, the Cassation Court. Many in the capital worried of an organized plot when other explosives were found outside at another bank outside Rome. In Genzano, 29 kilometres south of the city, a number of canisters full of petrol with electrical cables attached were found outside a bank along with a painted anarchist symbol and the slogan 'Set fire to the banks'. But police said the alarm was unfounded.