"I really liked him," classmate Clint McClellen said. "Nicest kid. Quiet, shy, kept to himself, but I liked that about him."
Dr. Laurence Steinberg, an expert in psychological development during adolescence, said that it is common for others to say that there did not seem to be anything wrong with a young perpetrator. He said signs of trouble often surface in the days following an event, as an investigation unfolds.
"It's extremely unlikely that a perfectly normal 17-year-old kid would take out a shotgun and kill members of his family," Steinberg told ABCNews.com.
"There's a little bit in what he said that sounds a little psycho-pathological in a sense that he does not seem to have the emotional response to what he did," he said. "Being callous and unemotional is a classic sign of a psychopath, so maybe he has some tendencies in that direction."
But Steinberg cautioned that sometimes it can be difficult to differentiate between shock and someone who is just unemotional.