NEW YORK — The woman who was allegedly murdered and then dismembered by an 83-year-old Brooklyn serial killer was beaten and died from a blow to the head, the city’s Medical Examiner’s office said Saturday. An autopsy of Susan Leyden’s scattered remains showed that she died of “homicidal violence including blunt force trauma to the head,” a spokeswoman for the Medical Examiner’s office said. Her death has been ruled a homicide. Leyden, 68, was reported missing March 2. The next day, her headless, limbless torso was discovered stuffed in a shopping cart on Pennsylvania and Atlantic avenues in E…
