Bill and Chuck hated Vic and agreed to start a fight with Vic and, if the opportunity arose, to kill him. Bill and Chuck met Vic in the street outside a bar and began to push him around. Ray, Sam, and Tom, who also hated Vic, stopped to watch. Ray threw Bill a knife. Sam told Bill, "Kill him." Tom, who made no move and said nothing, hoped that Bill would kill Vic with the knife. Chuck held Vic while Bill stabbed and killed him.On a charge of murdering Vic, Tom is
not guilty, because mere presence, coupled with silent approval and intent, is not sufficient.  not guilty, because he did not tell Bill ahead of time that he hoped Bill would murder Vic.  guilty, because he had a duty to stop the killing and made no attempt to do so.  guilty, because he was present and approved of what occurred