UPDATE, 9/13/13, 4:50 p.m. EDT: Information on a motion to intervene filed Wednesday by DLA Piper on behalf of the Sergeants Benevolent Association has been added to the fourth paragraph below.

In the weeks since New York Mayor Michael Bloomberg's administration filed a motion to appeal a federal court judge's ruling that the New York Police Department's stop-and-frisk practice violates the constitutional rights of citizens—and requested that the court halt the implementation of a series of police reforms until the appeal is decided—at least three Am Law 100 firms have jumped into the controversial case.

At issue is U.S. District Judge Shira Scheindlin's August 12 decision that found stop-and-frisk violates both the Fourth Amendment prohibition against unreasonable searches and seizures and the Fourteenth Amendment's equal protection clause, because the policy disproportionately target blacks and Hispanics. Over an eight-year period, 83 percent of the police department's stops involved blacks and Hispanics, though members of those minority groups make up just about half of city residents. As part of the ruling, Scheindlin also issued a preliminary injunction against stop-and-frisk encounters that violate the U.S. Constitution, ordered reforms of NYPD policies and practices, and appointed a monitor from Arnold & Porter to oversee changes in the 35,000-officer department, sibling publication New York Law Journal reported at the time.

Several New York police unions, represented by Dechert, filed a motion to intervene in the case Thursday, saying, "These remedies will directly touch upon the rights and interests of the members of the NYPD, including rights subject to existing collective bargaining with the city of New York," such as training, supervision, monitoring, and discipline. The unions, including The Patrolmen's Benevolent Association of the City of New York and the NYPD Captains Endowment Association, say they represent more than 29,000 members of the police department.