chunk: When Lanning falls to his death from his office window, the CEO of USR Lawrence Robertson declares it a suicide, but Spooner is skeptical. Spooner and robopsychologist Susan Calvin consult USR's central artificial intelligence computer, VIKI (Virtual Interactive Kinetic Intelligence), to review security footage of Lanning's fall. Though the video is corrupted, they learn that no other humans were in Lanning's office at the time; but Spooner points out that Lanning could not have thrown himself through his heavy office window—only a robot could have generated the necessary force. Calvin protests that this is impossible, as no robot can violate the Three Laws, but they are then attacked by an NS-5 robot, USR's latest model, in violation of the Laws. After the police apprehend it, they discover that the robot, nicknamed Sonny, is not an assembly-line NS-5, but a unique individual built by Lanning himself, with a secondary system that bypasses the Three Laws. Sonny also appears to have