[AnAmericanAbroad]

I’m very curious to know the nature of this “altercation” as well. Fortunately, the fourth person is still around to tell the tale. Smells like a motive.

There’s nothing worse than a person who bears a grudge.

[Enterprise]

The motive remained a mystery, and it was unclear why Lanza had argued with staffers at the school on Thursday.

It DOES stand out doesn't it? It appears clear that there WAS a prior incident, so maybe they can use that as a starting point for motive.

[Hieronymus]

If he got three of the four that he had confronted the day before, that would explain half of the staff fatalities. I imagine that he was looking for the fourth one as well and not finding her took out her class. Assumably the other adults were in the wrong place at the wrong time or trying to intervene.

If something beyond vengance against the four he had had the confrontation with had been a motive, it probably could have been much worse, as it sounds like it wouldn’t have been that difficult to take out more classes given the lock-down respons adopted.

[donmeaker]

Holding a grudge is like taking poison, and expecting the other person to die.

[visualops]

Smells like a motive.

I did read the investigators had a definite line on a motive but declined to discuss it as yet.
He didn't so much murder his mother to take her guns, but murdered her with her own gun. I wonder if she kept them locked up away from him but he found them, or if she actually did trust him with the guns around? People often are not realistic about what others are capable of. She had to have known he wasn't right in the head but just could not conceive of him harming her?