FILE - Demonstrators wear jerseys with the face of Judge Sergio Moro, who is heading the Petrobras investigation, as they protest on Copacabana beach in Rio de Janeiro, Brazil, March 13, 2016.
FILE - Demonstrators wear jerseys with the face of Judge Sergio Moro, who is heading the Petrobras investigation, as they protest on Copacabana beach in Rio de Janeiro, Brazil, March 13, 2016.

SAO PAULO - Brazil's judiciary will not end systemic corruption unless society also demands change, the federal judge presiding over a massive graft investigation that may topple President Dilma Rousseff's government said.

Judge Sergio Moro, a hero to many Brazilians who has recently been criticized for pushing the boundaries of the law, compared the investigation he oversees to Italy's "Clean Hands" anti-bribery operation in the 1990s.

"Alone the justice system cannot resolve corruption, other institutions must work and the public must speak out," Moro said on Tuesday evening at a conference where security was so tight that journalists were only allowed to record him with pen and paper.

A white collar crime expert who has written a book on money laundering, Moro said Italy is undoubtedly a better place because of the Clean Hands operation.

Still, he said the investigation did not completely stamp out corruption because Italy's democracy and civil society were not strong enough to demand change.

The probe Moro presides over in the southern city of Curitiba revealed a cartel of Brazil's largest construction companies that siphoned billions of dollars out of state-run oil firm Petroleo Brasileiro SA, benefiting executives and potentially dozens of senior politicians.

Its revelations, along with a deepening economic recession, have spurred the largest protests in decades, with some 3 million people taking to the streets on March 13. Protesters have idolized Moro, waving banners to show their support for him as they call for President Dilma Rousseff's ouster.

The government declared all-out war on Moro and the investigation after he this month released a slew of phone recordings of former president Luiz Inacio Lula da Silva that appear to show he and Rousseff discussed trying to influence judges and prosecutors.

Rousseff, who unlike Lula is not under investigation, said the conversation was misunderstood and branded the recordings as illegal. Several days of anti-government protests followed their release on March 16.

Moro made the phone conversations public just hours after Rousseff appointed Lula, her mentor and predecessor, to her Cabinet. The position would have granted him immunity from all judges but the Supreme Court, but his status as minister is now uncertain, awaiting a final legal ruling.

The Supreme Court also asked Moro to answer questions about his decision to release the phone calls, drawing a written apology from him in a Tuesday court filing in which he lamented the uproar he caused.

"I understand that my ruling may have been considered incorrect, or even if correct may have brought controversy and unnecessary constraints," Moro wrote. He said his motivation was preventing the obstruction of justice and was not partisan.

At the time, Moro justified the release by saying the right to privacy was not absolute, mentioning the U.S. Watergate scandal. He said democracy required citizens know when their leaders "sought protection in the shadows."

"As a citizen I'd say Moro was totally justified, but as a lawyer... he can't," said David Azevedo, a criminal lawyer and professor at the University of Sao Paulo. "He should have sent those recordings to the Supreme Court."

Under Brazilian law, only the Supreme Court can preside over cases involving presidents, ministers and lawmakers.

Rousseff is facing impeachment over the unrelated issue of mismanaging public accounts. She denies knowing about corruption at Petrobras as the company's chairwoman from 2003 to 2010.

Lula, who was forcibly detained for questioning in the Petrobras scandal, has denied all wrongdoing and says he is the victim of a witch hunt. Both Rousseff and Lula have likened the attempted impeachment to a coup.