SAN FRANCISCO (AP) — One of three young transients accused of killing a Canadian who was camping during a music festival and a yoga teacher who was walking a dog pleaded guilty to second-degree murder on Monday. In exchange, prosecutors dropped two first-degree murder charges that could have kept in prison for life if convicted. Investigators and the criminal complaint also say they were found with the stolen gun, Carter's Volkswagen station wagon and Carey's tent, sleeping bag, day pack, passport and airline tickets.