ALBANY — In a ruling that could broaden the disclosure obligations of district attorneys, a Sullivan County Court judge found the testimony of three grand jury witnesses to be exculpatory Brady material and ordered prosecutors to disclose it to the defense.

The rare discovery order came in an unusual homicide case, in which a retired State Police commander is accused of shooting his 37-year-old son to death during a domestic disturbance. Judge Frank J. LaBuda, in a motion decision released last week, found grand jury testimony by the defendant’s wife about her son’s alcohol abuse and assaultive behavior was clearly favorable to the defense and must be disclosed.