There's always more to the story, but not sure how it'd justify what happened.
I've googled the victim's name, and based on my reading of several different articles, I have found:
> It was 1AM and outdoors so it was dark
> The kid was wearing dark clothes, had on a dark ski mask, and was carrying a knife
> The knife hasn't been been described
> The father states the son lunged at him with the knife
> Nothing has been released to say if that was the extent of the outdoor confrontation
> The father didn't know it was his son till the police took off the kid's mask
> Nothing has been released to say if the police were called before the killing
> A friend says the son was online playing video games till 10PM and was acting normally
> It is said that the son had a previous argument with the aunt
> The town where this happened, New Fairfield CT
, is affluent
> Pictures of the location where this occurred show it is an affluent area
> A town resident had recently walked in on a burglar so tensions were elevated
> The son was adopted by the father
> The father is a very popular teacher in town
> The father had previously been the son's teacher before adopting him
> The son's natural mother is a drug addict and has a criminal past
> The natural mother had a car accident while on crack which killed her daughter
> The son was raised by his natural grandparents before being adopted
> The son loved aviation, was a member of the Civil Air Patrol and wanted to join the Air Force
> There is no indication the son had a criminal past or was a troublemaker
> His fellow students are describing him as a normal, likeable kid
> The father had a background in security
> It is not known yet if the gun was legally registered
Clearly some here are of the "shoot first, ask questions later" camp, but not me.
A key question in my mind is WTF the father felt he was qualified to deal with the situation.
Wouldn't a better answer been to call the police and have the sister barricade herself till the cops could get there?
Clearly all we have is the version of events being told by the father, so we'll never know if things played out as he states.