Almost all 18,000 police departments across the U.S. issue officers tasers, or stun guns, which are meant to be a non-lethal weapon to help police subdue suspects. But tasers have proved controversial partly because, when misused, they can result in death. In a five-part series of original reporting, digging through court documents, police reports and public records, “Reuters” has documented more than 1,000 incidents since the year 2000 when people died after police fired tasers at them.