Ferman declined to comment Thursday.
If the prosecutor files a criminal case, it would represent a stunning fall for Kane, 48, who won in a landslide in 2012 to become the first woman and Democrat elected attorney general.
Kane has denied breaking any laws in releasing the investigative material.
"The attorney general has done nothing wrong or illegal and, to my knowledge, there is no credible evidence that she has," her lawyer, Lanny J. Davis, said in a statement Thursday. "She told the truth to the grand jury at all times. I hope the district attorney will reach same conclusion."
Kane's tenure has been marked by controversy over the last year, much of it generated by an Inquirer disclosure that she had secretly shut down an undercover "sting" investigation that had caught elected officials from Philadelphia on tape accepting cash.
That case was resurrected by Philadelphia District Attorney Seth Williams, who has charged a former Traffic Court judge and two state legislators with bribery.
If Kane is arrested, she would become the second Pennsylvania attorney general in modern history to face criminal charges. Ernest Preate Jr., a Republican, resigned in 1995 after pleading guilty to federal charges in connection with an illegal $20,000 cash contribution.
An arrest would not affect Kane's status as attorney general. Under the state constitution, elected officials who are charged with a crime may remain in office until they are both convicted and sentenced.
In his statement Thursday, Davis questioned how The Inquirer learned about the grand jury's recommendation: "I wonder why the supervising judge who appointed the special prosecutor to investigate the attorney general hasn't initiated a grand jury investigation of this leak or any of the other previous leaks from this same grand jury process."
For about six months, special prosecutor Thomas E. Carluccio has been directing the grand jury as it has heard testimony from numerous witnesses, including Kane and many of her top aides, to determine how details of a long-ago investigation of a Philadelphia civil rights leader appeared in a Philadelphia Daily News article in June.
The article suggested that a former state prosecutor, Frank G. Fina, had fumbled that investigation, and the leak appeared designed to raise questions about his competence.
Fina and Kane have been embroiled in a months-long dispute about how each handled cases, including the sting investigation. Fina, once the top public-corruption prosecutor in the Attorney General's Office, launched the sting in 2010, before Kane took office.
Kane has acknowledged that she knew some material from her office was given to the newspaper, but said the material she approved for release was not grand jury information. Her allies have suggested that her staff may have erred by providing additional prohibited information without her knowledge.
The Daily News article provided details of a 2009 investigation by state prosecutors that looked into financial matters involving J. Whyatt Mondesire, then the head of the Philadelphia chapter of the NAACP. Mondesire was never charged or publicly named as a subject of a probe until the Daily News story.
He has said he did nothing wrong, and has denounced the article and leak as unfairly damaging to his reputation.
The grand jury investigation of the leak was approved by former Chief Justice Ronald D. Castille at the request of William R. Carpenter, a Montgomery County Court judge.
Carpenter, a former prosecutor, presides over a statewide investigative grand jury - one that looks into matters involving Philadelphia and surrounding counties - that is the successor jury to the one involved with the Mondesire matter six years ago.
Carpenter appointed Carluccio, a criminal defense lawyer in Plymouth Meeting and former prosecutor in Delaware, as special prosecutor.
Efforts to reach Carpenter and Carluccio were not successful Thursday.
Ferman, Castille, Carpenter, and Carluccio are Republicans.
Kane has suggested that the grand jury investigation was a partisan attack, a complaint rejected by Castille.
Castille, who retired from the bench Jan. 1, said he had approved numerous leak investigations during his 21 years on the high court.
In ordinary circumstances, prosecutors from the Attorney General's Office present cases to Carpenter's grand jury, and the Attorney General's Office later makes an arrest based on the panel's recommendation.
In this unusual leak investigation, however, the judge handed Ferman the role of prosecutor because she is district attorney in the county in which the grand jury meets.
Ferman is conducting an independent review of the grand jury presentment, sources say, a process that could take several months.
Philadelphia lawyer L. George Parry, a former prosecutor, said it made sense for Ferman to dig into the facts independently.
While arrests are typically made immediately after a presentment has been issued, Parry said, "this is really an unusual situation.
"I wouldn't fault her at all for wanting to review this," he said. "They are dropping a real hot potato on her. If, in fact, there is a presentment that calls for charging the attorney general of Pennsylvania, I would think that any responsible adult would want to read over things very carefully before committing to take on the case."
Ferman announced this week that she would run for a county judgeship in November and would serve out her term as district attorney.
While highly unusual, the prospect of a county prosecutor bringing a case against a statewide official is not unprecedented nationwide.
In August, a special prosecutor appointed by a judge charged Texas Gov. Rick Perry, a Republican, with two felonies for allegedly trying to force a Democratic district attorney out of office. Perry and other Republicans, and even some Democrats, have criticized the charges as political.