The third member of the gang, Gianni Bottura, is found dead, killed with the same weapon of the two previous murders. Erika Hedl travels to Italy to work with Lorenzo Fabbri, and meets the architect Giuliano Polidori, who was in the police station to sign the deposition for the discovery of Weber. Between the two sparks, and begin to get out together. Meanwhile investigations are continuing, and emerge telephone contacts between the latest victim and the girlfriend of Weber. Subsequently, the victim of the robbery recognizes accidentally Ferreri, who had visited his house in a job interview: Locksmiths understands that it was an inspection for the robbery, and that she was the fourth member of the gang. Once in her home, the woman seems to have disappeared, and is then found hanged in a cottage nearby. For Chief Commissioner the case is closed, but something is wrong: Ferreri could not have committed suicide because he suffered from arthritis in the thumb that prevented her from making the noose, and especially as he had to understand that they were on his trail? On closer analysis of the report on the robbery, Fabbri noted that the invested woman was the girlfriend of Polidori. He tries to reach Erika, on vacation with him, and in the end, thanks to the providential help of Rex, traps Polidori, who had approached Erika only to retrieve information and thus take revenge on that band.