Investigators say a man who was shot and killed by a U.S. Border Patrol agent in the mountains near Otay Mesa threw several large rocks at the agent, including one the size of a basketball. The San Diego County Sheriff's Department said that the attacker began throwing fist-sized rocks at the agent from a hillside perch. The rocks got larger, and one of the bigger pieces hit the agent in the head. The Sheriff's Department says the agent fired his gun twice fearing that he might be killed or incapacitated if he was hit again. the agent was treated for minor injuries at a hospital and released. This latest incident has fueled debate about how the Border Patrol should respond to rock attacks.