Rocco Mattarella, a successful restauranteur, has been shot dead in his own restaurant. Prof. Dr. Lisa Wolter reconstructs the crime. Apparently the victim was killed by nine shots, all fired from close range. Joachim Stoll immediately suspects this could be a warning from the Mafia, intended to frighten other restaurant-owners. When Jan Arnaud discovers that nothing is missing from the cash desk, and a threatening letter addressed to the victim comes to light, demanding protection money, it looks as though Joachim’s theory could well be correct. It now emerges that other landlords in the neighborhood have been subjected to pressure: Jean Krause, who runs the Lobby 0711 bar, shows Joachim Stoll a threatening letter he claims to have received just a couple of days earlier.
However, Martina Seiffert and Anna Badosi are of the opinion that the murder could be connected with the victim’s private life: not long ago Rocco Mattarella left his wife Elena for the young waitress Giulia Grassi. Now that Rocco is dead, all his property and assets go to Elena… while if she had divorced him, she would certainly have had to settle for far less. What’s more, Elena’s brother is none other than the infamous criminal Leonardo Livatino, who is widely suspected of involvement in organised crime even though nothing has ever been proven. It is well known that he wasn’t happy when his sister chose to marry Rocco in the first place, which would provide him with a motive. However, Elena and Leonardo claim to have been at home together at the time the crime was committed, thus providing each other with an alibi. When another bar owner, Rico Schrotti, contacts the police and claims to have been threatened, Stoll and Sander go undercover and position themselves in the bar, ready to catch the criminals. But things don’t go according to plan: the men manage to knock Rico out and escape. Anna Badosi now discovers that Leonardo doesn’t have an alibi after all, because his sister wasn’t at home at the time of the killing. However, there is no evidence that he was involved in the murder. Martina Seiffert and Anna Badosi do find out from him, though, that the victim was quite unscrupulous in his business practices. Now our investigators catch the men who attacked Rico Schrotti, and they finally confess to running a protection racket. But they absolutely deny any involvement in the murder. If they’re telling the truth, who really did kill Rocco Mattarella?