The Priest - S2.E6

A parish priest is found shot outside of a hostel in what apears to be a cold blooded execution. Wallander and his colleguaes are searching for clues while the priest, who is believed to be able to identify the perpetrator, is fighting for his life in hospital. The police pursues the crime as a crime of passion after discovering that he has had an extra marital affair. Bur where is the weapon, and which of the betrayed parties has the strongest motive?