>> we need you to wait ougd of the house. >> the detective was soon on coachside lane. he still had only a garbled account from the 91 1 call. who had shot who? >> your son was trying to protect you? >> yes. >> it looked like it was what we would call a domestic murder. it was something that just occurred. >> on arrival the first deputies on the scene saw a young man who would turn out to be 19-year-old charlie tan, standing in the driveway with his mother. >> they're outside the house. >> outside of the house. it's a safety thing for the deputies. no reason to go in so those people come out. they asked who was in the house? >> in the next moments the deputies heard the son tell a story that sounded like self-defense. he had to shoot, he said, to save his mother. he used a shotgun. >> charlie said my dad is in there. he is dead. i had to do it. he was going to hurt my mom. >> father was shot because the boy feels his mother is in