SAN JOSE, COSTA RICA (AP) An American tourist who watched as a U.S. military veteran in his 70s used his bare hands to kill an armed assailant in Costa Rica said she thought the attempted robbery was a joke until the masked attacker held a gun to her head. "I thought it was a skit. But then he pointed the gun at my head and grabbed me by the throat and I thought I was going to die," Clova Adams, 54, told The Associated Press by telephone Friday from the Carnival cruise ship Liberty.