Unbelievable that they arrest the Swiss man...This happened a couple of times in the last year in the bay area. California law around this is:
California Penal Code 198.5 PC explains that a person will be presumed to have a reasonable fear of imminent harm when someone unlawfully breaks into their home. If the person, while in their own home, uses deadly force to protect themselves and their family, it can be justified as self-defense