http://www.bbc.co.uk/news/world-us-canada-30356534

I have no doubt that there's racist undertones and all-round thuggishness to such killings (the NYPD rivals the Met. for sociopaths), but how the fcuk are they being trained in the first instance?

I put it down to the gun culture there. Police are scared that suspects will be armed and possible violent, so they shoot first and ask questions later. A 'rather them than us' attitude.