The sheriff’s corporal who was shot to death early Wednesday morning in Norridgewock had been involved just days earlier in arresting the girlfriend of the man now sought in his killing. Cpl. Eugene Cole, 62, of the Somerset County Sheriff’s Department, was shot and killed early Wednesday on U.S. Route 2 in Norridgewock, marking the first Maine police officer killed in a shooting in nearly 30 years. The shooting suspect, who remained at large and is considered by police to be “armed and extremely dangerous,” has been identified as John Williams, 29, of Madison. A massive police manhunt has been underway for Williams since Wednesday morning, involving the FBI and some 200 law enforcement officials who have scoured a number of locations across central Maine.