Onlookers included at least one youth, and when a passenger told a bus operator about the lewd act, Thomas-Dorsey exited the bus and fled, the agency said.
Metro Transit Police reviewing video footage recognized Thomas-Dorsey from an incident the night before, Metro said.
In that incident, Thomas-Dorsey allegedly was seen masturbating on a Silver Line train between Metro Center and L’Enfant Plaza about 8:45 p.m. Monday. He was arrested after a passenger pointed him out on the L’Enfant platform. But Thomas-Dorsey was released by D.C. Pretrial Services that night on a citation, Metro said. Indecent exposure constitutes a misdemeanor in the District.
Metro said officers arrested Thomas-Dorsey again late Tuesday night at his place of employment, which was not specified.
Maryland court records show Thomas-Dorsey was previously charged with indecent exposure in July 2013.