(NEWSER) – It looks like earlier reports about bullying playing a key part in yesterday's California school shooting were right. The 16-year-old unnamed shooter allegedly composed a list of students he wanted to kill last year, and told authorities he had been bullied for more than a year, reports the Bakersfield Californian. "Certainly the two people that he targeted had bullied him, in his mind," says the local sheriff. The suspect reportedly drew up plans for the attack on Wednesday night, and used a shotgun belonging to his brother, reports CNN. He arrived at school with his pockets full of ammunition after classes had begun yesterday morning, gaining access through a side door.