Cherie Freeman, a retired nurse in Tucson, Ariz., said last week she thought the number of attacks may hide a link to the al Qaeda terrorist network. At the time, the sniper had killed nine people and shot a total of 11, she noted, and last year's terror attacks are commonly referred to as "9/11."
"This guy apparently normally goes for the head," she said. "I think both of those [survivors] were intentional non-kills."
The theory, which she admitted was a little "off the wall," appears to be in trouble since now 12 victims have been officially linked to the sniper, and investigators are trying to determine if a shooting this morning in Montgomery County, Md., is tied to the sniper. A bus driver was shot on a commuter bus at about 6 a.m. ET and died in an area hospital.
Theories Swamp FBI Tip Line
The amount of amateur detective work has become a headache for the FBI.
FBI officials report that the hotline set up for tips about the case has been flooded with people offering their theories and hunches.
The agency publicly discouraged people from using the number to give their personal hypotheses about the case.
"We ask callers, however, to make sure that they provide substantive information relating to the sniper attacks; but not theories, opinion or unrelated information which needlessly tie up the tip line," the FBI said.
Instead, the FBI asked people to use the bureau Web site (www.fbi.gov) or a mailbox (P.O. Box 7875, Gaithersburg, MD 20898-7875) to send in their theories, where agents can review them at a more measured pace.
Part of the frenzy of speculation is due to the dearth of evidence made public in the case.
There is no sketch or description of a suspect, and it is unclear even if there is just one individual responsible for the attacks. Some witnesses have reported seeing two people in vans or trucks speeding away from several crime scenes.
The sniper's method of pursuing his victims is unlike most serial killers, who often kill their victims at close range, sometimes after sexually assaulting them.
Thrill Killer? Terrorist?
Many killers strike out of rage or some dark sexual impulse, but the sniper's motives are mysterious. Is he a "thrill killer," attracted by the challenge and danger of murdering innocent strangers? Is he trying to terrify the general public, or to extract revenge for some personal wrong, or a calculating terrorist part of a larger plot? Criminologists, retired law enforcement officials and other experts have suggested these and other theories.
One ABCNEWS.com message board user wonders if the location of the attacks is significant. Maybe the killer is trying to draw police resources away from the metropolitan D.C., area, as part of some grander plot, the writer suggests. The writer acknowledges the idea came from the movie Die Hard III.
Investigators themselves have shown they are open to unusual theories. The FBI is studying the pattern of the sniper's attacks on maps to try to determine if the sniper is trying to draw some kind of symbol.
Further, the public's most tantalizing clue — a tarot card with the death character — is also perhaps the most puzzling. Did he leave it to taunt police or mislead them, or was it left by someone else altogether? Does it signify an interest in the occult, or is it just a dramatic calling card chosen by whim?