Steve Jenner is slain at the opera and the assumption is that he was killed in mistake for Wilby's boyfriend Jonathan. In fact, after Wilby 's suicide, it is revealed that he was Wilby's secret lover and the police are baffled as to how the killer knew. Kate seeks out Jameson, who tells her that the link to the previous murders is the retired forensic scientist Dr Bannerman but then Bannerman's wife is also killed. Red learns that MacIntyre, Wilby and Bannerman were all involved in the murder of Carl Brown, for which Brian Herd was imprisoned, protesting his innocence. Duncan Warren also worked on the case and fears that his son Sam or new girlfriend police clerk Anna may be the next target of the avenger. Whilst Red visits the dying Herd in prison to establish any link to the current murderer the fact that the killer is so well-informed leads the team to surmise that it is somebody within the police ranks and they must act quickly to catch them.