The Legal Aid Society, in a suit filed Monday in Manhattan Federal Court, is asking a judge to declare unconstitutional the "practice of secretly taking, analyzing and maintaining peoples' DNA in its suspect index." The public defenders group seeks an order the NYPD expunge those DNA files and records.

There are 31,826 DNA profiles in the database at last count, according to the suit.

The database, which is maintained by the Office of the Chief Medical Examiner, has been the subject of much debate the past few years.

The NYPD said it operates within the bounds of the law and that the database is an important tool used to obtain justice for each crime victim.

But critics have said any policy that allows police to collect DNA without consent — such as by offering a suspect a soda, then keeping the can for forensic analysis, even if the person is not charged with a crime — is a violation of privacy rights.