At the Soviet equivalent of Los Alamos, Arzamas-16, physicist Yuli Khariton led the scientific effort to develop the weapon. Beria distrusted his scientists, however, and he distrusted the carefully collected espionage information. As such, Beria assigned multiple teams of scientists to the same task without informing each team of the other's existence. If they arrived at different conclusions, Beria would bring them together for the first time and have them debate with their newfound counterparts. Beria used the espionage information as a way to double-check the progress of his scientists, and in his effort for duplication of the American project even rejected more efficient bomb designs in favor of ones that more closely mimicked the tried-and-true Fat Man bomb used by the U.S. against Nagasaki.