(Adds details of comments, background on investigations)
By Ricardo Brito
BRASILIA, June 19 (Reuters) - Brazilian Justice Minister Sergio Moro said on Wednesday that a criminal organization was responsible for alleged leaks of his private messages as a federal judge, which raised questions about his ethics while overseeing a major corruption probe.
Moro is facing calls for his resignation after text messages published by news website The Intercept allegedly showed he pushed prosecutors to turn public opinion against former president Luiz Inacio Lula da Silva, whom he convicted of bribery last year.
In Senate committee testimony on Wednesday, Moro questioned the authenticity of the messages attributed to him and said some may have been doctored by those seeking to overturn convictions in the record-setting "Car Wash" corruption investigation.
Moro said he had nothing to hide and blamed organized crime for what he called a hacking attack.
"They are doing this to undermine the anti-corruption drive, which was not an achievement by me or prosecutors, but by Brazilian society," he said. "I have nothing to hide."
Moro said he always acted within the law during "Car Wash," which he oversaw until last year. In November he became justice minister under right-wing President Jair Bolsonaro, who won the presidency after Lula was barred from running because of his conviction.
Moro has said he will not resign, and Bolsonaro has said there is "no chance, zero" of Moro being forced out.
The texts, allegedly exchanged over the Telegram messaging app, appear to show Moro suggesting to prosecutors in May 2017 that they mount a public campaign against Lula, the defendant he was judging.
Lula's lawyers demanded a retrial, saying the messages raised doubts about Moro's impartiality in the trial that led to a 12-year prison sentence for Lula.
Lula's was the highest-profile conviction in what U.S. prosecutors have called the world's largest graft investigation, which has brought down scores of businessmen and politicians in Brazil and across Latin America since 2014.
Investigators uncovered billions of dollars in bribes paid in schemes mostly involving sweetheart contracts with state-run firms such as oil company Petroleo Brasileiro SA. (Reporting by Ricardo Brito; Writing by Jamie McGeever and Anthony Boadle; Editing by Chizu Nomiyama, Bill Trott and Jeffrey Benkoe)