The Police Department in Manchester, N.H., has confirmed that one of its undercover vehicles is being investigated in connection with a hit-and-run crash that injured two pedestrians in Bedford. Two people were hit Friday night at about 9:20 p.m. while walking on Harrod Lane; authorities said the driver fled without stopping. One victim suffered head trauma and was taken to a local hospital with serious injuries, police said. The other was taken to the hospital with minor injuries. Authorities said the undercover vehicle was assigned to Detective Sergeant Stephen Coco, who has been fired for violating several of the department’s standard operating procedures.