Attorney General Eric Holder announced two initiatives Thursday to address concerns about police services in Ferguson and St. Louis County, Missouri.

In addition to the ongoing criminal civil rights investigation of the shooting death of African-American teenager Michael Brown by a white police officer, Darren Wilson, on Aug. 9, the Justice Department, through its Civil Rights division, has opened a civil pattern and practice investigation into allegations of unlawful policing by the City of Ferguson Police Department.

The second initiative is a Collaborative Reform Initiative with the St. Louis County Police Department -- as the county administers programs for officers throughout the area.

A local grand jury is also investigating the shooting, which set off two weeks of protests and demonstrations in Ferguson and became the center for discussion of police treatment of minorities across the U.S.

The attorney general visited Ferguson two weeks ago and met Brown's parents.

"I had the chance to speak to a number of local residents. I heard from them directly about the deep mistrust that has taken hold between law enforcement officials and members of the community," Holder said. "In the meetings and listening sessions -- as well as information conversations -- people consistently expressed concern stemming from specific alleged incidents, from general policing practices and from the lack of diversity on Ferguson's police force."

Holder said the investigation will assess the department's use of force, including deadly force, and will analyze stops, searches and arrests. And the investigation will examine treatment of people in Ferguson's city jail and other potentially discriminatory practices.

A 2013 report by the Missouri attorney general found Ferguson police stopped and arrested black drivers nearly twice as frequently as white motorists but were less likely to find contraband on black drivers.

The Justice Department has opened 20 pattern and practice investigations into police departments across the country, and the Civil Rights Division has prosecuted 300 officers for misconduct. The division just completed a three-year investigation of the Newark Police Department, in which it found routine use of excessive force, unwarranted stops, theft and racism.

The division has also reached agreements with New Orleans over patterns of excessive force by police officers and is moving ahead with implementing reforms in training, interrogations and arrests. Holder said the mayor, city manager and police chief in Ferguson have welcomed the investigation.

Responding to the announcement, Missouri Senator Claire McCaskill said in a statement the investigation was a step in the right direction toward "taking a hard look at police practices and civil rights enforcement in Ferguson."