The sniper who apparently struck again on Tuesday defies easy classification by experts who disagree whether he is a serial killer or a spree killer. Serial killers tend to take long ‘‘cooling off’’ periods between murders and have sexual motivations, whereas spree killers, angry and paranoid at a recent loss, act in a compact time period, experts say.Both differ from mass murderers, who kill many people in one intense burst, often after losing a job or a relationship. The sniper’s initial six killings within 28 hours led experts to classify him as a spree killer. But with an apparent 14th shooting on Tuesday, 20 days after the first incident, experts say he is showing a methodical pattern closer to serial killings.‘‘He’s kind of a cross between a spree killer and a serial killer. He doesn’t fit into one category,’’ said Tod Burke, a criminal justice professor at Radford University in Virginia and former policeman. Experts say serial killers often target a type of person the way David Berkowitz, who was angry at and frustrated with women, attacked and killed several young women in New York in a 13-month span in 1976 and 1977. But the sniper appears indifferent to the gender, age and race of his victims, choosing them by location, and deliberately moving around to defy geographical profiles.‘‘This is more a mocking of the police and institutions than of the victim,’’ said Leo Barrile, a criminologist at Bloomsburg University. Serial killers are much more common than spree killers and include such people as Ted Bundy and ‘‘Unabomber’’ Theodore Kaczynski. (LATWP)
