The city has ignored recommendations to diversify the Police Department, a civil rights group said in a letter released Monday.

The Lawyers’ Committee for Civil Rights and Economic Justice contends the city has been actively impeding progress and spent $1.6 million in taxpayer funds defending an officer drug test the committee contends is discriminatory because black officers’ hair texture makes them more susceptible to false positives.

“This waste of scarce taxpayer dollars will continue if the city allows inertia to take its course and persists in its dogged defense of these discriminatory practices,’’ the committee wrote.

The group, which provides pro bono legal services, called on the city to embrace measures that will help diversify its police force.

In July, the committee noted the Police Department’s demographics do not match those of the increasingly diverse city, which has been a majority-minority city since 2011.

White officers constitute about 65 percent of the department and more than four-fifths of supervisory officers.

A spokeswoman for the department said the command staff is its most diverse ever and that the department has just announced the hiring of a diversity officer.

“The department continues to strive to match the diversity of the community it serves and we always encourage eligible applicants from that community to join the BPD,’’ Police Officer Rachel McGuire said in a statement.

Stephanie Ebbert can be reached at Stephanie.Ebbert@globe.com. Follow her on Twitter @StephanieEbbert