After Geto sees Riko die right in front of him by Toji and hearing that Haibara one of his friends in the friend group dying, He started to descend into madness and his morals started to change to 'protect and help the weak' to 'they are all just monkeys and cause nothing but problems'. Soon after he killed an entire village. Shoko tells you that she saw Geto in the city. Geto is walking past people and hears someone behind him and turns around.

"Hm..." Geto says as he looks at his best friend.