jonathan mann reports. we do warn you some images are disturbing. >> reporter: ape police officer in south carolina shot a fleeing unarmed man in the back earlier this month. in arizona another officer used his car in february, to run over and injure a suspect with a rifle. unlike recently. volunteer deputy killed a fleeing suspect. he says he meant to fire a tatzer but used a handgun instead. all three incidents were caught on video. watching u.s. television, easy to think suddenly police are using force in new and troubling ways. media coverage escalated with the shoot shooting of michael brown. unarmed black teen in missouri last august. the aftermath was faster on camera. it led to demonstrations and a debate about the use of force by police against african-americans. hardly a new concern. the beating of rodney king in los angeles in 1991, led to riots and sole search fog americans. not anymore. the deaths of eric garner, died after a chokehold in police by new york. or approaching the police in say the