U.S. Attorney General Eric Holder addresses the Justice Department's findings in two investigations regarding the Ferguson, Missouri shooting of Michael Brown by Darren Wilson in Washington March 4, 2015. [Photo/Agencies]

WASHINGTON - The US Justice Department has concluded that the Ferguson, Missouri, police department routinely engages in racially biased practices, a law enforcement official familiar with the department's findings said on Tuesday.

The investigation into the police department began in August after the shooting of unarmed African-American teen Michael Brown by a white police officer in Ferguson sparked national protests.

Analysis of more than 35,000 pages of police records found racist comments from officers as well as statistics that showed African-Americans make up 93 percent of arrests while accounting for only 67 percent of the population in Ferguson, the official said.

African-Americans also made up most of incidents in which officers used force and all incidents where police dogs bit citizens, said the official, who asked not to be named because of the sensitive nature of the investigation.

Nationwide protests of police actions that resulted in deaths of African Americans in Ferguson, New York and Cleveland laid bare racial tensions and what President Barack Obama called "simmering distrust" between police and communities.

The findings are expected to be formally released as early as Wednesday, a Justice Department spokeswoman said. The department will use the findings to negotiate policy changes with Ferguson officials and enter a consent decree, or to sue the city to force change.