WEST HEMPSTEAD, N.Y.—A gunman shot three workers inside a manager’s office at a Long Island grocery store Tuesday, killing one of them, police said. A manhunt was underway for the gunman, who had also worked at the store, said Nassau County Police Commissioner Patrick Ryder. The shooting happened around 11 a.m. inside an office upstairs from the shopping floor at the Stop & Shop in West Hempstead, Ryder said. There were about a “couple hundred” shoppers inside the store at the time. The name of the victims have not been made public. The man who was killed was a 49-year-old store employee, Ryder said. The two wounded were hospitalized and were conscious and alert. Police identified the suspected gunman as Gabriel DeWitt Wilson and gave a date of birth for him indicating he is 31 years old. It was unclear whether he was still employed by the store, Ryder said. …