Dietl said it is not far-fetched to suggest high school students could pull off so many crimes while leaving so few clues.
"Everyone has to be vigilant, and you report what you see," Dietl said. "If you get a feeling if something is not right with your neighbor, call the police. The only way they're going to break this case is by a tip from the public."
Michael G. McGrath, a professor of forensic psychiatry at the University of Rochester School of Medicine and an expert on behavioral profiling, said the sniper appears to be carefully planning his attacks.
"My guess is that this is not someone who is simply driving around and saying, `Gee, this looks like a good gas station.' He obviously knows the area very well and has escape routes planned," McGrath said.
He added, "We know this person has not taken a shot and stayed waiting to see what happens. They are taking a shot and bolting, leaving the area as quickly as they can."
Bartholomew said he doesn't envy the task that police face in trying to capture the killer.
"You've almost got to be right on top of him," he said. "And the police can't be everywhere."
Sun staff writer M. Dion Thompson contributed to this article.