The Nashville school shooter had planned the massacre for months in advanced and studied other mass murderers before killing six people, police have said. Audrey Hale, 28, had detailed writings plotting her sick attack months before she butchered three kids and three adults at The Covenant School last week. Cops also revealed on Monday that she fired 152 rounds from two assault rifles and a handgun during the vile shooting that rocked the US. Officials haven't released a motive for the slaying of victims Hallie Scruggs, William Kinney, Evelyn Dieckhaus, all 9, and headmistress Dr Katherine Koonce, 60, substitute teacher...