HARRISBURG — A new legal front opened for Attorney General Kathleen Kane after a judge said she must explain whether her firing of a prosecutor violated his 7-month-old order not to retaliate against witnesses in an investigation into allegations her office leaked secret grand jury information.

Friday’s order by Montgomery County Judge William Carpenter, who supervised the grand jury investigation, came two days after Kane’s office fired a prosecutor, James Barker, who had testified before the panel.

Lanny Davis, an outside lawyer for Kane, said in a statement Friday that all of Kane’s personnel decisions were appropriate management decisions to promote reform and efficiency in the office. Davis did not refer to Barker by name. He also did not say whether the attorney general’s office would challenge the judge’s order to appear, or the protective order he issued last year.

The grand jury recommended in December that Kane be charged with criminal contempt, perjury, obstruction, false swearing and official oppression stemming from allegations that her office gave secret investigative material to a newspaper last year. Its written report has not been disclosed publicly and Montgomery County District Attorney Risa Vetri Ferman is looking into its findings.

Barker testified before the grand jury, but has declined to discuss his testimony. Kane has not been charged with any crime and has maintained that she is not guilty of leaking secret information.

During last year’s investigation, Carpenter issued the protective order to shield grand jury witnesses from “obstruction, intimidation or retaliation” by anyone, including employees of the attorney general’s office. Carpenter’s order had been sealed, but he made it public for the first time Friday.

Carpenter set an April 27 hearing for Kane and Thomas Carluccio, the special prosecutor in the grand jury investigation, to appear before him and two other judges to address Barker’s firing. The panel will then decide whether the protective order was violated. If they decide it was, a hearing would be held to determine whether to impose a contempt of court punishment.