New York police are investigating a bizarre mystery involving groups of people emerging from the city’s manholes in recent weeks. Video recorded on May 29 shows seven people climb through a manhole at the intersection of Bedford Avenue and Lynch Street in Brooklyn.“The NYPD, to make sure there was not a threat to the public, sent their highly trained Emergency Services Unit officers into the sewer system to make sure nothing nefarious had been left behind by the individuals – nothing was found,” the New York City police department told NBC in a statement on 1 June