Seattle Police Chief John Diaz is out. After three tumultuous years at the helm of an embattled police department, Diaz announced on Monday that he will retire, the [Seattle Times](http://blogs.seattletimes.com/today/2013/04/seattle-police-chief-john-di...) reported. His announcement comes while his department is in the throes of a federally initiated reform process, and has come under renewed scrutiny for its slow pace of improvement. The Department of Justice entered into a reform agreement with Seattle police last year after finding in an investigation that Seattle police officers used excessive force nearly 20 percent of the time when they used force, and engaged in racially biased policing. The Justice Department initiated its investigation after a rash of public and well-documented incidents of police brutality against men of color, including the [shooting death](http://colorlines.com/archives/2010/09/seattle_demands_answers_after_cop...) of a Native American man and a videotaped incident of Seattle police officers [stomping](http://colorlines.com/archives/2010/09/no_hate_crime_charges_for_seattle...) on a Latino man and hurling racial epithets at him. Diaz was the first person of color to hold his position. Seattle Mayor Mike McGinn has named Assistant Chief Jim Pugel the department's interim head.