An institutional problem in Boston area police departments?

Just as the controversy over the arrest of black scholar Herny L. Gates at his Cambridge home by a white police officer appeared to be nearing an end, a Boston police officer has written a letter to the Boston Globe comparing Gates (multiple times) to a “jungle monkey”: “If I was the officer he verbally assaulted like a banana-eating jungle monkey, I would have sprayed him in the face with OC deserving of his belligerent non-compliance. “  Officer Justin Barrett has been suspended; he insists he is not a racist.   (Barrett’s lawyer explains that his client’s comparison would have been “much less offensive, if [his client had] used a different species of animal.”  [!])  Mayor Menino wants him fired.  Watch the NECN report, via boston.com.  Is this a free speech issue?  Is it evidence of an institutional problem in Boston area police departments?  As the Boston Globe reports, detective Larry Ellison, president of the Massachusetts Association of Minority Law Enforcement Officers,  points to multiple incidents, including that of a white officer who posted an article, “Slavery: Best Thing that Ever Happened to Blacks.”  For more on police department culture, see the blog of sociologist and police officer Peter Moskos .