HELP ME FIND THIS MAMHWA PLS ;^;

ok so basically its set in a dystopia world where these government bots roam around "helping" civilians. mc sees his bestfriend get killed by one of these bots in broad daylight but everyone forgets abt it, acting like nothing happened. he then goes on a little journey to find out whats REALLY going on. the genre is thriller horror mystery?? also the bots kill humans to turn them into some sort of fuel l.