NORRIDGEWOCK, Maine — A Madison man suspected of shooting and killing a Somerset County sheriff’s deputy early Wednesday morning remained at large Thursday, the second day of a nationwide manhunt to find him. John D. Williams, 29, allegedly shot Deputy Cpl. Eugene Cole sometime before 2 a.m. Wednesday, stole the officer’s marked cruiser and robbed a Cumberland Farms convenience store on Route 2 before ditching the cruiser on nearby Martin Stream Road, according to police.