By Philissa Cramer and Ron Kampeas The man charged with killing 10 people at a Buffalo, New York, supermarket Saturday allegedly was motivated by a conspiracy theory that has spurred recent deadly attacks on Jews, among others. An online manifesto attributed to Payton Gendron, 18, explains that the attack was spurred by the theory that a tide of immigrants is crowding out white populations in western countries. The manifesto also says that Jews are the real problem but that “they can be dealt with in time.” The Tops supermarket, located just a few miles from the Canadian border, was chosen...