(CNN) The Justice Department has filed a lawsuit against the Baltimore County, Maryland, Police Department, alleging it engaged in "unintended" racial discrimination in its hiring practices over the last six years.

The department made hiring decisions "based on the results of hiring examinations that were not job-related and that disproportionately excluded African American applicants," the DOJ said in a statement announcing the lawsuit.

The Justice Department says it wants a court to order Baltimore County police to use selection processes that comply with Title VII of the Civil Rights Act, the federal anti-discrimination law.

Since 2013, the county used at least three different versions of a written exam to screen entry-level police officer and police cadet applicants, according to the complaint.

In that time, African Americans passed at a consistently lower rate than white applicants, and the difference between the two remained statistically significant, the complaint, filed in the US District Court for the District of Maryland, says.

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