Cops are looking to question a trio of straphangers who were caught on video propping open a subway exit door in Brooklyn — hours after an anti-cop rally descended on the city’s transit system.

One man was caught on station surveillance cameras tying a shirt to an exit door inside the Fulton Street and Franklin Avenue subway station to keep it open around 10:45 p.m. on Jan. 31.

Moments later, a pair of women can be seen placing a lock on the same door to keep it open before strolling through without paying the fare, according to the video.

The incident came just hours after demonstrators flooded Grand Central Terminal to protest police presence on the transit system.

The NYPD released surveillance footage from the station on Wednesday.