Two officers in a remote Alaska town were ambushed as they chatted on a street. Two California deputies were killed by an arson suspect with a high-powered rifle as they tried to serve him a warrant. Two other officers doing anti-drug work were gunned down by men along a busy Arkansas highway.

These so-called cluster killings of more than one officer helped make 2010 a particularly dangerous year for law enforcement. Deaths in the line of duty jumped 37 percent to about 160 from 117 the year before, according to numbers as of Dec. 28 compiled by the National Law Enforcement Officers Memorial Fund, a nonprofit that tracks police deaths.

Why do you think there's been an increase in police fatalities?

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