Portsmouth police are searching for a missing teenager who was last seen more than a week ago.Davyn Hanson, 15, was walking away from Portsmouth High School last Monday around 3:15 p.m., according to police. Hanson has brown eyes, bleached blonde shoulder-length hair and is 5 feet, 6 inches tall. Officials said he was last seen wearing a red, white and blue-striped shirt and jeans.Portsmouth police say Hanson has ties to the Somersworth and Rochester areas.Police are asking anyone who has seen the teenager to call them at 603-610-7534.