Shots rang out across a Phoenix apartment complex one cool desert night last December. A patrolman arrived to investigate. Cleophus Cooksey Jr., 36, answered his knock at the door — covered in blood. His mom and stepdad were dead inside. Within just days (short work for crime-solving), detectives discovered that distinct markings on the bullets from the apartment matched others from violent crime scenes across the Phoenix area. This so-called ballistic analysis tied Cooksey’s guns to nine gruesome murders that had occurred over a three-week period.