SAO PAULO - Brazilian prosecutors on Tuesday accused U.S. journalist Glenn Greenwald of involvement in hacking the phones of officials involved in a corruption investigation, but said court rulings protecting free speech prevent them from bringing charges.

A prosecutor in the Federal District, Wellington Divino Marques de Oliveira, said the journalist helped a group of six people who hacked into phones of hundreds local authorities.

Greenwald's The Intercept Brasil published excerpts from conversations involving Justice Minister Sergio Moro, saying they showed the then-judge was improperly coordinating with prosecutors at the time he was a judge overseeing a vast corruption investigation. The probe led to the imprisonment of former President Luis Inacio Lula da Silva on corruption charges.

While many Brazilians hail Moro as a hero, others believe he unfairly targeted da Silva and other top leftist figures. Moro is now a key member of far-right President Jair Bolsonaro's cabinet.

Greenwald's attorneys said in a statement that the prosecutors' allegations are "bizarre" and that they challenge the top court ruling protecting the journalist and freedom of press in Brazil.

"Their objective is to disparage journalistic work," the lawyers said.

Prosecutors said in a statement that an unreleased audio links Greenwald to the group of hackers as they broke the law, terming it "auxiliary participation in the crime" and saying he was "seeking to subvert the idea of protection of a journalistic source into immunity to guide criminals."

Brazil's top court last year said that "the constitutional secrecy" around journalistic sources prevented the Brazilian state from using "coercive measures" against Greenwald. Because of that, a judge would have to authorize any attempt by prosecutors to formally investigate Greenwald or bring charges.

Greenwald, an attorney-turned-journalist who lives in Brazil, has frequently come under criticism by Bolsonaro.

Moro has not acknowledge the veracity of the reports by The Intercept Brasil, saying they come from "criminal invasion" of the phones of several prosecutors. Many others involved in the leaked messages or mentioned in them have confirmed their content.