Older brother of Alexander Roby and a prominent city banker. He is a portly, bearded middle-aged man with some resemblance to https://en.wikipedia.org/wiki/George_V King George, and looks nothing like his brother.

• He was one of the three men to sign Alexander's committal papers after the Roby Murders (along with Doctor Charles Highsmith and Doctor Lionel Trollope; he was unwilling to see his brother released).
• When interviewed by Dr Bartlett, he was belligerent and unhelpful, making it quite clear that he considers his brother to be a dangerous killer. He also suggested that Delia Hartston was in some way involved with the murders.
• According to Doctor Lionel Trollope's last letter, Grahame hired Vincent Tuck to investigate Alexander's associates.