This story is from early 2001. The boy was bullied and was also accused of making threats.
“The unidentified 16-year-old boy had no history of violent behavior. Even so, the horror story he wrote about blowing up a school was enough to land him behind bars. “
“[Stephen King] himself issued a brief statement about the case, observing: “It has been a time-honored custom to put people in jail or bully them because of their imagination.” “
More details here:
“According to his parents, the boy wrote the story shortly after he was attacked by a gang of 11 youths. They said he was pushed to the ground and kicked in the head repeatedly, leaving him covered in blood.”
So they arrested him for his story and specific threats he was alleged to have made. I wonder if they jailed the bullies! But of course the bullies were only stupid and violent and not in need of any psychological evaluation I guess.
Canadian writers defended him:
“Rather than becoming violent, he got creative,” said [Sean] Wilson, who organizes the Ottawa International Writers’ Festival. “I think he should be applauded for that.”