A man wearing a medical face mask was caught on camera sucker-punching an NYPD officer in the Bronx Tuesday night as the cop’s partner was subduing a robbery suspect. Nelson Jimenez, 31, launched his attack in front of a crowd of bystanders who had gathered on a sidewalk near 183rd Street and Davidson Avenue in University Heights to watch the arrest of 27-year-old robbery suspect Yoemdy Castro, law enforcement sources said. One cop in the video can be seen holding Castro to the ground, while another stands nearby.