Promoted to avoid deadly force, Tasers can sometimes be part of a fatal police equation

FILE - In this April 4, 2015, file photo, from video provided by Attorney L. Chris Stewart representing the family of Walter Lamer Scott, Scott appears to be running away from City Patrolman Michael Thomas Slager, right, in North Charleston, S.C. Slager was charged with murder on Tuesday, April 7, hours after law enforcement officials viewed the dramatic video that appears to show him shooting a fleeing Scott several times in the back. (AP Photo/Courtesy of L. Chris Stewart, File) (The Associated Press)

In this photo provided by the Tulsa County, Oklahoma, Sheriff's Office is Eric Harris, 44. Police say Robert Bates, a white reserve sheriff's deputy, thought he was holding a stun gun, not his handgun, when he fatally shot Harris, a black suspect, during an arrest that was caught on video in. Harris was treated by medics at the scene and died in a Tulsa hospital. (Tulsa County Sheriff's Office via AP) (The Associated Press)

The officer who shot an unarmed black man during a South Carolina traffic stop says he fired in self-defense after a struggle over his stun gun.

Officer Michael Slager was charged with murder and fired after a video challenged his version. But the case points to a paradox in policing: Stun guns were meant to help police avoid using lethal force, but sometimes they become part of the problem.

The Associated Press found a half-dozen other fatal police shootings of black men involving stun guns recently.

The maker of Taser says its stun guns are "safe, effective and accountable." But a policing expert tells AP that stun guns can give officers a false sense of control, and civil rights advocates say police need to focus instead on de-escalating violent situations.