6 U.S. soliders in Afghanistan killed by turncoat Afghan Border Police officer

so, from what i understand from this short article is that 6 ( mostly) american soldiers were killed by a turncoat afghan police officer! it happened when the the soldiers were doing a training mission on the Pakistani border. this is not the first time that the afghan police officers swich sides ( joined the bad guys who killes the soldies) , and started to kill people!

i completely think that it was completely unsessasy to shoot the soldies, i mean, i'm not sure if they intention was to kill them, or they didn't know who they were??and, so do think these " police officers" need a punishment, i mean aren't they suppost to help the people too? and don't they know that the soldiers are trying to help?? what kind of " police officers" are these????