[Rich Miranda]

Someone who won't leave your property is a trespasser, especially if they aren't armed. Trespassing equals a fine and maybe a few days in jail, not the death penalty.

Also, why weren't the police called after the first incident?

The homeowner may benefit from his reputation as a grandfatherly-type, however.

Finally, who's to say that the teen made any move whatsoever toward the homeowner? We only have one side of the story. Maybe gramps got tired of arguing and offed the kid.