Harter Brocken: Die Kronzeugin(2017)

Overview:

A shootout, five fatalities and he himself wounded - in the otherwise quiet station of the village policeman Frank Koops, things are just like in the Wild West. The bloodbath was commissioned by the imprisoned mafia boss Petrovic, who wants to use all means to get rid of a key witness who was hidden in the tranquility of St. Andreasberg in the utmost secrecy.