Ellen Granahan Goffer, Pennsylvania Attorney General Kathleen Kane's twin sister, walks into the courtroom after a short recess on the second day of Kane's trial in Norristown on Tuesday.

NORRISTOWN — A desire for revenge drove Pennsylvania’s attorney general to leak secret criminal files to the press to embarrass a rival and then lie about it to a grand jury, prosecutors said as Kathleen Kane’s perjury and obstruction trial opened Tuesday.

Kane, 50, was once a rising star in the state’s Democratic party, using her then-husband’s trucking fortune to run for statewide office after stints as a Scranton prosecutor and stay-at-home mother. Her 2012 campaign criticized the pace of the office’s child sex abuse investigation of Penn State assistant football coach Jerry Sandusky.

The chief deputy attorney general, Frank Fina, had led that investigation. When Kane took office, he moved on.

The feud nonetheless sizzled, and she suspected him of planting a Philadelphia Inquirer article a year later that faulted her for not charging anyone in a statehouse bribery sting.

“I will not allow them to discredit me or our office,” Kane wrote to a media strategist that day, according to e-mails shown in court Tuesday. “This is war.”

Kane, out for revenge, gathered documents from a Fina-led grand jury case from 2009 that had likewise been dropped, prosecutors said. The case involved J. Whyatt “Jerry” Mondesire, an NAACP leader in Philadelphia. He became collateral damage when a story ran in 2014, they said.

“He was just a casualty in her war of revenge. She was after Frank Fina,” Assistant District Attorney Michelle Henry said in opening statements.

Kane had given the confidential documents to top assistant Adrian King, who passed them on to campaign consultant Josh Morrow, who passed them to the Philadelphia Daily News, she said. Rather than address her critics at a news conference, Henry said, Kane deployed “cloak and dagger” techniques.

Kane then lied repeatedly about the leak to a grand jury, Henry said.

“I don’t know what Adrian gave to Josh,” she told the grand jury, according to excerpts shown in court. “What I said to Adrian was, ‘People need to know about this.’ He agreed.”

Bruce Beemer, who headed the criminal section, testified that he was stunned when he saw the Daily News article because he knew the Mondesire leak must have come from their office. He returns to court today for more testimony.