LOS ANGELES, California (CNN) -- Federal prosecutors have launched an investigation into whether leaders of the Los Angeles archdiocese committed fraud by failing to properly deal with charges of priests molesting children, two law-enforcement sources told CNN.
The archdiocese said it has been contacted by the U.S. attorney's office for information on individual priests.
The Los Angeles Times and Wall Street Journal on Wednesday reported that Cardinal Roger M. Mahony is specifically targeted in a grand jury investigation -- citing unnamed government sources.
U.S. Attorney Thomas P. O'Brien is personally involved in the probe, according to the reports.
In a written statement, the Catholic archdiocese on Wednesday defended its actions. It said the archdiocese has been contacted by the U.S. attorney's office for "information about a number of individual priests" -- two who are dead and none of whom are active in the clergy.
"The archdiocese is not aware of any fact or set of facts that would support a responsible federal investigation of the archdiocese or of Cardinal Roger Mahony," said the statement.
While calling the Catholic church's history of sex-abuse "regrettable," the statement said abuse reports have served as a catalyst for reforms in the L.A. archdiocese.
"Under Cardinal Mahony's leadership, the archdiocese has become a model for organizations nationwide in the education, training and detection of every aspect of abuse," it said.
Advocates for victims of clergy abuse, however, were welcoming news of a possible probe.
Esther Miller, spokeswoman for Survivors Network of those Abused by Priests, called an investigation long overdue.
"Cardinal Mahony's cover up record was well documented; there is a lot of evidence out there ... ," she said. "People thought they were getting good priests, and indeed they were not. Cardinal Mahony knew this.
"Something has to change in order to protect kids at all costs."
For years, the Los Angeles district attorney's office has had an open investigation looking into sex abuse against children by members of the clergy. But Sandi Gibbons, of the district attorney's office, told CNN that the office has run into "statutory problems and corroboration issues," because many of the alleged crimes happened so long ago.
The archdiocese, with 288 parishes in 120 cities throughout southern California, serves more than 4 million Catholics, according to its Web site.
Mahony has dealt with accusations he covered up sex-abuse cases for years. Two years ago, the archdiocese agreed to pay $660 million to 508 people who claimed they were victims of abuse by priests.
The archdiocese criticized unnamed government sources for apparently leaking news of an investigation to the media.
"The leak by the government is unprofessional and violates Department of Justice guidelines concerning on-going investigations," Michael Hennigan, an attorney for the archdiocese, said in a written statement.
The archdiocese is calling for an investigation "to determine the extent and depth of misconduct by those who were responsible for the leak," according to the statement.
-- CNN's Drew Griffin contributed to this report.