Nine out of 10 of the deadliest mass shooters had a history of threatening or committing domestic violence. More than half of all mass shootings are family or domestic violence related. Experts say mass violence grows from more targeted behavior at home or at the workplace. At Mercy Hospital and Medical Center on Monday, three people were fatally shot by 32-year-old Juan Lopez. Lopez’s first wife got a restraining order against him. He was also dismissed from the fire academy for workplace aggression against women.