Anger against his mother then? The teacher could have triggered his anger IMO. Based on this article posted by i.b.nora.
Even as his mother prepared to drive the family back to her home state of Massachusetts in a beat-up van with no air conditioning, Philip Chism held out hope that she would reconsider, friends and neighbors said Friday. Their interviews shed light on the lanky teenagers life before coming to Danvers, and the distress the move may have caused.
Did he have any other behavioural problems at his new school? It seems everything was great back in Tennessee.
http://www.bostonglobe.com/metro/20...her-slaying/YUYYkOkVYUfk82VZpxQPBM/story.html
Everything was great in his new school also until it wasn't.