Hi. As a local I just wanted to say that this is not really a "gun" issue; despite what this kid's lawyer says about his never having broke the law, he has a history at the school that set alarm bells off when someone mentioned the gun, and repeated whatever he'd said.
His nickname among the other kids is "Creepy Ken", and apparently he's just that -- a determinedly odd kid who since moving to town has made a habit of doing and saying disturbing things. If you notice, the story doesn't get into details about what he said that made his friend tell the school; the word is he said something that worried the other kid. Apparently he has some on-going beef with one or more teachers (that don't make sense to anyone else). The school has been at a loss dealing with him for a while.
That's why, when they found the gun, they flipped. It's not about the gun itself, it's the kid, and the whole story, which hasn't been in the papers. That's why they're doing a psych eval on him; he's been an issue for a while. The cops say the story about getting rid of his grandfather's gun was just something he made up when they found it.
This is a wealthy town, with plenty of corporate big shots that carry protection; it's not about the gun, it's about this specific kid, and that they actually found one, loaded, in his car after he said something weird to another kid.