BERLIN—German politicians expressed shock on Tuesday over the killing of a 20-year old petrol station worker after an argument about a face mask and said that coronavirus deniers who are willing to use violence will not be tolerated. The killing on Saturday evening in the western town of Idar-Oberstein has hit the national headlines as it is one of the only such cases linked to COVID-19 restrictions. Prosecutors have said that the petrol station cashier had asked a 49-year old man who wanted to buy beer to comply with the rules and put on a mask. The customer refused and left but returned later wearing a mask which he pulled down when he approached the cashier who again referred to the rules. “Then the perpetrator pulled a revolver and shot the cashier in the head from the front. The victim fell to the floor and was immediately dead,” prosecutor Kai …