The latest shooting by a sniper in suburban Washington marks a new boldness that could end up being the killer's downfall.
The gunman shot his victim from an estimated 50 feet away, instead of a hundred yards or more. And the killer apparently stood out in the open in the busy parking lot as he took aim.
The perverse calculation of the serial killer, experts say, could indicate a feeling of invincibility that will prompt the gunman to take even greater chances.
"That ultimately [will] be his downfall, his arrogance," says James Fox, a criminologist at Northeastern University in Boston. "But if he does make a mistake, it's not because he wants to get caught: It's because he thinks he's uncatchable."
Indeed, the killer's ability to elude authorities so far is now causing some experts to reassess their profile: They believe that two people may be working in concert, one driving the getaway vehicle.
If it is one person, the shooter is unusually methodical. Experts say the character sketch that's emerging is one of a premeditated, thoughtful man or men who may pick their victims at random, but choose the locations and escape routes with great care.
"He obviously isn't picking a target, he's picking an opportunity," says Alfred Blumstein, criminologist at Carnegie Mellon University in Pittsburgh.
The ninth casualty on Sunday night was a woman simply loading packages into her car at the Home Depot in a busy shopping mall in Falls Church, Va. The fatal shooting has many of the earmarks of the earlier attacks a single shot, a white van, and the quick, clean getaway despite an almost immediate police response and a massive dragnet.
The attack took place after a three-day break, leading experts to suggest that the killer is operating with apparent care and thoughtfulness. Last week, Mr. Fox notes, there was a killing almost every other day.
He could have planned on Sunday, then attacked the 13-year-old Maryland boy outside his school on Monday. Tuesday could have been the preparation day for the shooter's Wednesday attack on the man in Virginia who was pumping gas.
"The ability to escape the way these people are doing, in my opinion, is because they are rehearsing," says Robert Ressler, a former FBI profiler and director of Forensic Behavioral Services International, a consulting company in Santa Rosa Beach, Fla. "They're probably surveilling the locations in another vehicle. These are planned, premeditated killings."
Other experts agree that the gunman or gunmen are planning their escape routes with care. Tod Burke, a professor of criminal justice at Radford University in Virginia, believes the killer or killers also have a designated hiding place.
"They have figured out how long it takes for this police dragnet to go into effect," says Mr. Burke. "[They are] either able to beat the traffic or he's maybe hiding his vehicle in a garage or wooded area nearby. He's waiting for things to cool down for the dragnet to lift and then he becomes mobile again."
The complexity of the operation leads Mr. Ressler to believe that it is likely that two people are involved.
Single serial shooters, historically, tend to be disorganized like Charles Whitman, the infamous sniper who gunned down people at random from the University of Texas Tower in 1966.
"When you get a pair operating as serial killers, they tend to be more organized, and they reinforce each other and support each other in their activities," says Ressler. "To set up, observe, shoot, break down, and then leave, I think it's got to be a two man operation."
Mr. Fox also believes that it could be two people one playing the general who gives orders, the other the soldier who enjoys praise for his loyalty and help.
"The sport of killing could be more enjoyable for them when doing it with a buddy, part of the thrill is the camaraderie," says Fox. "But I'd still lean more toward a single shooter. After all, the message [on the tarot card left in Maryland last week] did say, 'I am God.' "
Whether it's a single killer or a pair, the lack of any clear motivation, either political or hate-based, leads experts to believe this killing spree is a product of generalized rage against society. This person or persons have failed and been frustrated in some way, and now they're paying back the world by carving out a place in history, however infamous and short-lived.
"They're self-destructive. They know this is a high-risk game that will end up eventually in the loss of their lives," says Ressler. "But they're probably thinking of being in the history books of maniacs along with the likes of Jeffrey Dahmer and Charles Manson. They're pathetic losers."
Abraham McLaughlin contributed to this report.