It was my fualt

Their house had exploded. 

They said it was gas leakage. It was winter and the heating systems were working. The windows and doors were also closed all the time, making it more dangerous. They said that the explosion happened because Kairen switched the light. They said doing that had created a spark, and that spark was the thing that caused the explosion. They said such things happened in old houses a lot as the heating systems were either aged or not built safely. They said such incidents would happen throughout the world all the time.