Fewest police killed by firearms since 1887...citizens killed by police, well that's another story.

http://www.breitbart.com/Big-Government/2013/12/30/2013--fewest-police-deaths-by-firearms-since-1887

Since 2011, officer fatalities across all categories have decreased by 34 percent, and firearms deaths have dropped by 54 percent.

Fourteen officers died from heart attacks that occurred while performing their duties.

The report found that Texas and California had the highest number of fatalities, with 13 and 10, respectively.

http://en.wikipedia.org/wiki/List_of_killings_by_law_enforcement_officers_in_the_United_States