The New York Civil Liberties Union says a database with the names and addresses of hundreds of thousands of people stopped, questioned and frisked by police is illegal.
The NYCLU says state law requires that records relating to a summons or an arrest be sealed unless the person is convicted or pleads guilty to a crime.
It filed a lawsuit Wednesday in state Supreme Court in Manhattan.
The database grew out of a 2001 law. It required the NYPD to give lawmakers quarterly information on people it has stopped. Last year, the total was 575,304.
Police use the database as a tool to investigate crime. Police Commissioner Raymond Kelly said Wednesday he hasn't seen the lawsuit but reiterated the importance of the database.