"He feels an enormous rush of power as he picks off these people anonymously," suggests Mark Levy, M.D., FAPA, a forensic psychiatrist and assistant clinical professor of psychiatry at the University of California at San Francisco. "It compensates for an inherent sense of weakness and helplessness." Based on the current belief that there is no connection between the victims, it seems the sniper is trying to make others feel as he does: Impotent.

Criminal composites suggest the shooter is male, white and in his mid-twenties to forties. Snipers generally have poor interpersonal relations but do not stand out in the crowd. On the surface, they seem psychologically stable. "This is a guy who blends easily," Levy says. "He is probably quite innocuous. He's in a fairly paranoid state of mind, but he's not necessarily psychotic." A shooter such as this one has generally experienced a series of losses, personal rejections and financial setbacks that bring on isolation. And while he appears very rational in accomplishing his shots, "his thinking about what he is accomplishing is most likely delusional," Levy continues.

This type of mindset makes Levy worry that when captured, the shooter will very likely commit suicide. His apprehension at being caught would collapse the power gained through the random murders. "These people are usually quite depressed," says Levy.

For more information on Mark Levy, click on his Web site at www.lawandpsychiatry.com.