-- The police department of Ferguson, Missouri, the town where an unarmed black teenager was killed by a police officer last month, is now the subject of a federal investigation into its use of force, how officers stop and search, and how its officers are trained.
He said it was prompted by anecdotal complaints and a "variety of documents" that had information like "the percentage of stops for certain ethnic groups." He said there was "deep mistrust" of the Ferguson police and "lack of diversity" in the make-up of the force.
Holder said the probe will look into the Ferguson PD's use of deadly force, analyze who its officers stop and search, the make-up the department's arrests, treatment of suspects in jail, and the training of its officers.
The AG said that if the probe determined that any adjacent departments should also be investigated, "we will not hesitate."
The shooting of Brown, 18, is already under review by the Department of Justice as well as by a St. Louis County grand jury.
The officer who shot Brown, Darren Wilson, has not spoken publicly but the police department said that Wilson suffered a serious facial injury in the confrontation with Brown. Supporters and friends have said that Wilson fired because Brown kept advancing toward him.
Protesters in Ferguson had complained that the town's police department was overwhelmingly white while the town's population had a majority of black residents.
The city issued a two-paragraph statement vowing "our willingness to be transparent and forthright as we continue the process of earning back the trust of our residents and our neighbors in the St. Louis region."
During Holder's news conference he was asked if the department had completed its investigation into the death of Trayvon Martin, an unarmed teenager who was shot to death in 2012.
"That investigation is ongoing," Holder said.
The Justice Department's civil rights division routinely investigates individual police departments when there are allegations of systemic use-of-force violations, racial bias or other problems. The department says it's opened 20 investigations in the past five years, more than twice the number opened in the previous five years.
The investigations typically encourage significant changes to policies and practices and often end with settlements — known as consent decrees — in which the department agrees to make specified reforms.
The Associated Press contributed to this report