Steve Chapman's article in Reason on police accountability is good throughout, but these stats are amazing:
Consider Cleveland. The ClevelandPlain Dealer reported that the police department looked into 4,427 uses of force by cops over four years and gave its blessing to each one. In Houston, every shooting over six years was found by the internal affairs department to be absolutely necessary. ...
The feds also assume that law enforcement officers are less fallible than the pope. From January 2010 to October 2013, the Los Angeles Times reported, Border Patrol agents shot 67 people, killing 19. Three of the agents are still being investigated. Of the remaining 64, 62 were absolved. The other two got a stern lecture.
It's all part of a national pattern. Bowling Green State University criminologist Philip Stinson has done extensive research on killings by cops. His conclusion? "It's very rare that an officer gets charged with a homicide offense resulting from their on-duty conduct even though people are killed on a fairly regular basis," he told The Wall Street Journal.
I have already given my cynical take on why this problem exists and why it is likely to persist. Specifically, Conservatives fetishize the police and refuse to believe any shooting was unjustified and Liberals are suspicious of the police but refuse to challenge the powerful public employees unions that protect police from accountability.