(CNN) -- A former Alabama university professor accused of gunning down three colleagues in February was indicted in Massachusetts on Wednesday in the 1986 shooting death of her brother.
Amy Bishop was charged with first-degree murder in the killing of her brother, Seth Bishop, Norfolk District Attorney William Keating said.
The brother's death originally was ruled an accident. His death came under renewed scrutiny after Amy Bishop was arrested February 12 in a shooting rampage at a biology faculty meeting at the University of Alabama-Huntsville.
At the time of the 1986 killing, Bishop, who was 21, told authorities she had asked for her 18-year-old brother's help unloading a shotgun when it accidentally discharged.
Keating acknowledged Wednesday mistakes in handling the case, saying "jobs weren't done, responsibilities were not met and justice was not served."
"Three individuals who were killed in Alabama may not have been" had Bishop been charged in her brother's death, Keating said.
Bishop is awaiting trial in Alabama on capital murder and attempted murder charges in the university shooting. Three people were injured in the attack.