BRASILIA, July 15 (Reuters) - Brazil's Justice Minister José Eduardo Cardozo pledged on Wednesday to punish any investigators found to have broken the law by using unauthorized bugs or leaking documents to the press while probing corruption at state-run oil firm Petrobras.
The landmark probe that has jailed powerful engineering executives and implicated dozens of politicians is coming under scrutiny for lengthy pre-trial detentions and other aggressive tactics some lawyers say flout the law.
Former executives at Petroleo Brasileiro SA, as the company is formally known, and some of its suppliers are accused of inflating the value of service contracts and funneling extra money back to themselves and to political parties, including that of President Dilma Rousseff.
Cardozo said he had not had access to an ongoing federal police inquiry over a bug found in convicted money launderer Alberto Youssef's cell. Two officers said it was not authorized by a court, and Cardozo warned of serious consequences.
"If that is proven it is extremely grave," Cardozo, who oversees the federal police, told a congressional inquiry. "The Justice Ministry will not tolerate irregularities."
An unauthorized bug could be particularly damaging to the investigation in Brazil, a country where legal cases are frequently thrown out because of procedural errors.
For instance, a high-profile money laundering investigation at Camargo Correa, one of the engineering firms also under investigation in the Petrobras case, was dismissed in 2011 because phones were tapped based on an anonymous tip.
Questioned about a series of high-profile leaks in Brazilian media, including plea bargain testimony with the names of politicians who allegedly received bribes, Cardozo said the leaks were "illegal" and "criminal".
Veja magazine last month published testimony from Ricardo Pessoa, who prosecutors say may have led an alleged cartel of engineering firms. Veja reported, without saying how it obtained the testimony, that part of the money resulting from overpriced contracts was donated to the campaigns of several politicians, including Rousseff's 2014 re-election.
Rousseff and her party said all donations were legal and registered with electoral authorities. Her approval rating has cratered because of the investigation and a sharp economic downturn.
Cardozo emphasized that plea bargain testimony is not enough to prove guilt. He warned that investigating leaks would prove difficult as journalists are allowed by law to protect their sources. (Reporting by Maria Carolina Marcello; Writing by Caroline Stauffer; Editing by Christian Plumb)