Attorneys involved in an almost 50-year-old case in the Southern District of New York sent a series of questions to the New York City Law Department on Monday, asking whether the New York City Police Department is illegally interrogating people arrested during police brutality protests about their political affiliations.

The arrestees were questioned by NYPD officials and FBI agents despite being arrested on minor charges, including curfew violations, according to the letter, which was put to city lawyers by attorneys who won a 1971 case restricting the questioning of protesters.

Handschu v. Special Services Division, which was filed in 1971 in connection with police surveillance of anti-war protesters, led to the creation of the "Handschu guidelines," which have been revised over the years but continue to govern when and how the NYPD can investigate political and religious activities.

"We have been here before," attorney Martin Stolar wrote in Monday's letter.

Similar issues arose as recently as 2014, when arrestees protesting the killing of Eric Garner were questioned about their "political and associational activities," Stolar wrote.

In 2015, Lawrence Byrne, then-NYPD deputy commissioner for legal matters, informed Handschu class counsel and the court that the questioning of people arrested during protests required "explicit advanced authorization by the [NYPD] Legal Bureau … to ensure that the Handschu guidelines are either not applicable to such questioning or are fully complied with if applicable."

Stolar and his colleagues saw Byrne's letter as a positive step, they wrote, which made recent reports all the more concerning.

Protesters arrested in the past two weeks have reportedly been asked questions including "What do you know about antifa?" "What do you do to organize protests?" and "What social media accounts do you follow?" along with other inquiries related to social media activity, protest leadership and alleged membership in antifa or anarchist groups, according to the letter.

Stolar and his colleagues asked the Law Department to inquire as to whether the NYPD is currently complying with Byrne's 2015 directive. They also asked a series of questions about how many protesters have been interrogated and by whom, along with any legal justification for the questions.

In a statement, New York City Law Department spokesman Nick Paolucci said the department is reviewing the allegations with the NYPD and will respond.

"The NYPD is committed to adhering to the Handschu guidelines," Paolucci said.

Read more: