Washington (CNN) -- A federal investigation of the Seattle Police Department for possible excessive use of force and discriminatory policing was launched Thursday, Justice Department officials announced.
Although the Seattle Police Department has been plagued by several reports of improper arrests and unwarranted beatings that led to a preliminary review, federal officials insisted the probe was not triggered by any specific incidents or allegations.
Assistant Attorney General for Civil Rights Tom Perez and the U.S. attorney in Seattle, Jenny Durkan, emphasized in a call with reporters the investigation is civil, not criminal. They said rather than seeking to resolve any specific cases, the "pattern or practice" investigation will focus on Seattle police systems of enforcement and on policy changes that may need to be made.
Perez said the probe will be much narrower than a similar investigation of the New Orleans Police Department, but noted Seattle and New Orleans have both fully cooperated with federal authorities.
The officials stressed that neither the federal preliminary review nor the full "pattern or practice" investigation announced Thursday had been triggered by a letter from the American Civil Liberties Union and more than 30 civil rights groups calling for a full-blown investigation. Perez said the preliminary review had already been started when the Justice Department received the letter in early December.
That letter cited six alleged incidents of particular concern that the ACLU claims require a wide-ranging investigation:
-- June 11 2009: An African-American man being released from jail was tackled, kicked in the face and beaten with a baton by three officers, according to the ACLU letter.
-- April 17, 2010: Police stopped a Latino man they believed might be a robbery suspect. Video shows that while the man was lying on the sidewalk an officer kicked him in the face and threatened to beat him. Another officer then stepped on his legs, the letter says.
-- April 24, 2010: One of the same officers involved in that incident arrested a young man after a bar fight. The man was handcuffed, placed in the back of a patrol car, where, he claims, the officer repeatedly choked him, the civil rights groups allege.
-- June 14, 2010: A police officer saw young people jaywalking and confronted a teenage African-American girl. The letter says video of the incident shows that after she put her hands on him, the officer punched the girl in the face.
-- August 30, 2010: A Seattle police officer shot and killed John T. Williams, described as belonging to a First Nations Tribe. The man, a wood carver, was seen on video crossing a street holding his carving knife. When he didn't drop it, the officer shot him. The ACLU letter says it is unclear if Williams, who was partially deaf, heard the order. A preliminary review board has found the shooting unjustified.
-- October 18, 2010: A convenience store camera shows an African-American teenager with his hands in the air being kicked by a police officer, causing him to fall to the ground. After he was kicked several more times, the teenager was handcuffed by a second officer, according to the letter.
The Justice Department declined to comment on any specific incidents but issued a written statement saying, "Today's announcement is separate from any ongoing federal criminal investigation involving the Seattle Police Department."
The Seattle Police Department has taken action on its own in some of the incidents. There was no immediate comment from the department Thursday.