Who spotted Frank Robert James first? That’s the question on the minds of many after several sharp-eyed citizen sleuths said they saw the suspected Brooklyn subway shooter wandering Manhattan’s East Village and alerted the NYPD. After police declared the 62-year-old a suspect in Tuesday’s mass shooting that saw 10 people shot and 13 others injured, a $50,000 reward was offered for information leading to his arrest and indictment. Photography student Jack Griffin, 17, was on a field trip with his class when he said he spotted James.