On a South Carolina Shooting

Regarding this story/video of a police officer shooting a running black man eight times, I am not as interested in stories about these particular individuals and their backstories as I am in stories about:

• Why the police officer actually felt like he had to shoot a running suspect
• Why the police officer felt so secure/confident about framing the murdered man with a Tazor.
• How we can address the many situations like this where its not caught on video.