A blind desire for revenge led 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 news 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 emails shown in court Tuesday. "This is war."

Kane, out for revenge, gathered documents from a Fina-led grand jury case that had likewise been dropped, prosecutors said. The 2009 case involved J. Whyatt "Jerry" Mondesire, an NAACP leader in Philadelphia. He became collateral damage when the 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 got them to the Philadelphia Daily News, she said. Rather than respond to criticism at a news conference, Henry said, "it's cloak and dagger."

Kane then lied repeatedly before a grand jury investigating the leak, Henry said.

The defense told jurors in opening statements that Kane wouldn't have risked her career over a feud with Fina, a prosecutor who landed a job in Philadelphia.

"(He) left 10 minutes after she arrived," veteran New York trial lawyer Gerald Shargel told jurors. "It just does not make sense that she would risk her reputation and her career (over him)."

But Fina, with the blessing of Philadelphia District Attorney Seth Williams, fanned the flames when he revived the statehouse probe and secured several convictions. Kane had deemed the case flawed by sloppy detective work and a focus on black lawmakers from Philadelphia.

Kane is charged with perjury, a felony, and misdemeanor counts of conspiracy, obstruction and false swearing. She lost her law license over the charges and did not seek re-election this year. The trial is expected to last a week.