SANTA FE, Texas (AP) — A gunman carrying a shotgun and a revolver opened fire at a Houston-area high school Friday, killing 10 people, most of them students, authorities said. It was the nation's deadliest such attack since the massacre in Florida that gave rise to a campaign by teens for gun control.The suspected shooter, who was in custody, also had explosive devices, including a molotov cocktail, that were found in the school and nearby, said Gov.