Michael Slager, the former South Carolina police officer convicted in the 2015 killing of unarmed 50-year-old Walter Scott, has been sentenced by a federal judge to 20 years in prison. Slager, a white man who was working with the North Charleston Police Department at the time, was convicted of second-degree murder and obstruction of justice in the shooting death of African-American Scott. Slager claims he shot Scott in self-defense, but a cellphone video shot by an eyewitness depicted him firing at Scott's back as he ran away. The sentence was passed by U.S. District Judge David Norton. Slager was charged with Scott's murder in South Carolina, but that case ended in a mistrial. Before the sentence was read, Slager apologized by name to each member of Scott's family, saying “I wish I could go back to the day and change the events, but I can’t.” – ABCNEWS