LOS ANGELES (AP) — A California appellate court has heard arguments on behalf of Michael Jackson’s mother for a new trial in her lawsuit against concert giant AEG Live LLC.

Attorneys for Katherine Jackson told a three justice panel of the 2nd District Court of Appeal in Los Angeles that a new trial should be ordered because jurors who decided a nearly six-month trial in AEG’s favor last year were given an improper verdict form.

Katherine Jackson sued AEG, the promoters of her son’s ill-fated “This Is It” comeback concerts, claiming they were responsible for her son’s 2009 death because they hired the doctor who administered a fatal dose of anesthetic.

AEG’s lawyers however argue that the Jackson family matriarch’s attorneys sought the exact question jurors used to decide the case in AEG’s favor.