The mayor of Berlin says that left-wing political extremists are most likely behind the attack on the city's electricity infrastructure that left tens of thousands of homes without power. Residents have been told that they may have to wait several days for full power restoration. Police say they received a letter claiming responsibility from a known extremist group, and they consider the claim credible. Chapters: 0:00 Berlin mayor blames extremists for power outage 2:28 Hans-Jakob Schindler,