A Houma teen, who pleaded guilty to driving drunk when he wrecked his car, killing his girlfriend, was sentenced to 10 years in prison. State police say Stephen Murphy was driving with Amanda Doyle, of Houma, on Dec. 11 when he lost control, hit a mailbox and flipped into a water-filled ditch. Police say Murphy, who was 18 at the time, was driving 81 mph in a 45-mph zone and had more than two times the amount of alcohol in his system allowed by law for a person under 21. Murphy, who was sentenced Thursday, pleaded guilty to vehicular homicide, which carries up to 30 years in prison. Murphy will serve his first five years in prison without parole, according to his attorney Gregg Graffagnino.