By DAVID FISCHER MIAMI (AP) — Brian Laundrie, who was found dead last month in a Florida swamp, shot himself in the head, officials announced Tuesday. Laundrie had been the subject of a manhunt for more than a month as investigators searched for clues in the slaying of his girlfriend, Gabby Petito, during their cross-country van trip together. The medical examiner in Sarasota County, where Laundrie's