The Center for Privacy & Technology at Georgetown University law school sued the New York Police Department on Tuesday to demand access to documents associated with its use of facial-recognition technology.

According to the privacy group, the NYPD had initially released one document in response to a freedom of information request in January last year, as part of The Perpetual Line-Up, a year-long study on law enforcement uses of facial recognition technology by the researchers. The group contends that this is not enough since there was evidence to show that the NYPD frequently used a sophisticated facial-recognition system in recent years.

Law enforcement use facial-recognition databases to tag possible criminal suspects, and this is all conducted by an algorithm that searches images stored in databases and comparing them with other images to help in the identification of a person believed to be committing a crime.

The technology has been criticized due to concerns that it is flawed, and results in false positives. There are also accusations of racial bias in the identification process.