To the Police Department, its database of stop-and-frisk interactions is an invaluable tool, providing quick access to data that can solve crimes and save lives… In court papers on Wednesday, the New York Civil Liberties Union filed a lawsuit to stop the Police Department from keeping information on those who were arrested as a result of the stops, but later cleared of criminal charges or had their charges downgraded to a violation… “Innocent New Yorkers who are the victims of unjustified police stops should not suffer the further injustice of having their personal information stored indefinitely in a sprawling N.Y.P.D. database,” Donna Lieberman, the executive director of the civil liberties group, said in a statement. “With this database, the N.Y.P.D. is turning innocent black and Latino New Yorkers into criminal suspects.”