A long article in The Guardian; with a sub-title:
Police in Kern County, California, have killed more people per capita than in any other American county in 2015. The Guardian examines how, with little oversight, officers here became the country’s most lethal
In 2015:
In all, 13 people have been killed so far this year by law enforcement officers in Kern County, which has a population of just under 875,000. During the same period, nine people were killed by the NYPD across the five counties of New York City, where almost 10 times as many people live and about 23 times as many sworn law enforcement officers patrol.
Link:http://www.theguardian.com/us-news/2...olice-killings

There is an interesting table for:
America's deadliest counties for police killings this year Among all US counties with five or more officer-involved killings logged by the Guardian in 2015, Kern County saw the most deaths per capita.*
The deadliest counties — those with 10 or more deaths – are show below