The most detailed and promising lead yet in the serial sniper attacks dissolved yesterday as officials said a potentially critical witness intentionally misled them, leaving detectives with scant clues in their hunt for the shadowy killer terrorizing the Washington suburbs.
Police said a citizen's detailed description of a gunman wielding a Soviet-style assault rifle and escaping in a cream-colored van after Monday night's killing of a 47-year-old woman in a suburban Virginia shopping center had proved false, dimming hopes for a quick capture.
Left with no apparent motive for the attacks and few promising clues to the sniper, investigators redoubled their efforts on existing leads and at the crime scenes. Dozens of federal agents returned yesterday to Falls Church, Va., near the site of Monday's shooting, where they stopped cars to examine tire treads.
Investigators also looked more closely at the possibility that the sniper killings could be linked to international terrorism, with FBI agents planning to question al-Qaida prisoners held at the U.S. naval base at Guantanamo Bay, Cuba, to determine any possible links to the sniper. The killer's seemingly random, single-shot killings - nine in all - have reshaped everyday suburban life.
A federal law enforcement source confirmed the plan to interview al-Qaida detainees. Officials have said repeatedly that they do not believe that there is such a link, but investigators say they have not ruled out any theories as fears about the sniper shootings have spread well beyond Washington.
There was some relief yesterday - the sniper did not strike for a third day in a row, the longest stretch without gunfire since the shootings began Oct. 2. But police also were facing the grim reality that the killer could remain elusive unless there is another shooting that might lead to his capture or yield new clues.
After Monday's killing outside a Home Depot store, police had expressed guarded optimism about detailed accounts from witnesses at the busy Seven Corners shopping center. Police said one witness described having seen the shooter fire a Soviet-style AK-74 assault rifle within 40 yards of the victim, then flee in a cream-colored van with a burned-out left tail light.
But after interviewing other witnesses, authorities said yesterday that the man's account was unreliable and should be disregarded. The witness, who has not been identified, could face charges for making false statements to police, though some experts cautioned that most false witness reports are the result of human error.
"The information provided by one of the witnesses at the scene of the shooting in the Home Depot, describing a cream-colored van with a malfunctioning taillight, is not credible," said Fairfax County police Chief J. Thomas Manger.
Manger said the man's description of the sniper's rifle as an AK-74 also was "not reliable."
The reversal came as police have taken extraordinary measures - from creating geographic profiles to drawing composite sketches of suspicious vehicles to highway dragnets - to solve the sniper attacks in Maryland, Virginia and the District of Columbia.
In spite of the profiles, the deployment of roughly 1,000 officers and approval of the use of military spy planes, the sniper remains free and investigators concede that much remains unknown, including whether the shooter is acting alone.
Investigators have given no indication that they are any closer to understanding the sniper's motivation today than when the killings began. But as the case has unfolded, detectives have begun to form a handful of theories based on the killer's targets.
His most consistent characteristic has been to target people doing everyday activities, such as pumping gas, mowing a lawn, going to school or shopping at suburban commercial centers. But another curious element in several of the shootings has been their proximity to Michaels crafts stores, a common fixture in many suburban shopping centers.
So far, three people have been shot at or near a Michaels. Police do not know whether it is a coincidence or an intentional pattern, but it has prompted them to look at perhaps the most puzzling gunshot of all: the killer's first, fired Oct. 2, less than an hour before his murderous rampage began.
That bullet smashed through a Michaels store window at 5:20 p.m. in an Aspen Hill shopping center in Montgomery County. It hit no one - the only shot fired by the sniper that did not.
A law enforcement official familiar with the investigation said a handful of detectives working on the case theorize that the bullet had special significance, perhaps representing a message from the killer.
"It's possible it was a signature of some sort," said the official, who spoke on condition of anonymity. "Maybe he was delivering a bullet that police would always be able to match up to his soon-to-be committed crimes."
It's also possible, he said, that the killer was "earmarking" Michaels for some reason. Investigators have looked into the possibility that the killer might have worked at a Michaels. Other investigators have theorized that Michaels stores are often located in large shopping centers, and that the killer is sending a message that he will strike in such locations.
Officials with the chain of national stores have said they are cooperating with investigators.
The Michaels connection is rarely overlooked in the dozens of theories circulating about the invisible shooter, some of which have surmised that the crafts store and the sniper share the same name or that Michaels is being invoked as a spiritual reference to St. Michael the Archangel, whose name means "Who is like God?"
The only known correspondence between the sniper and police came in the form of a tarot card left at the scene of a shooting at a school in Bowie with the handwritten message: "Dear Policeman, I am God."
Authorities have said they have no evidence linking the attacks to foreign terrorist groups and that they are questioning the detainees at Guantanamo Bay about whether sniper shootings were ever discussed as a tactic in al-Qaida training camps or manuals.
The questioning, said one official, is routine.
"This shouldn't surprise anybody," a law enforcement official said. "We don't know if there's a connection; we're just covering every possible theory."
FBI Director Robert S. Mueller III, appearing at a congressional hearing about intelligence failures connected to the Sept. 11 terror attacks, declined to comment about the sniper investigation.
Homeland Security Director Tom Ridge said this week that there is no evidence that the shootings were linked to al-Qaida, but added: "Certainly, the FBI and no one in the White House has foreclosed it."
Montgomery County police Chief Charles Moose declined yesterday to talk about whether the shootings might be a link to terrorist groups. But Moose and others played down news reports that investigators had spoken to witnesses who had described olive-skinned or Middle Eastern-looking men fleeing the shooting scenes.
The chief's comments came as he and Fairfax County's Manger disclosed that police now believe the witness' account from Virginia that had seemed to hold such promise is untrue.
Authorities contended that the discredited account was not a setback. Moose said investigators are chasing leads and soliciting new tips. He said composite sketches of a Chevrolet Astro van or Ford Econoline van that witnesses reported at the scenes of earlier attacks are still considered reliable.
"We continue to be confident that this case is going to be solved and is going to end in an arrest," Manger said.
Moose said police officials came out aggressively yesterday to rebut news reports about the witness' account to prevent subsequent stories that might influence potential witnesses.
"People saw a description of a weapon over the last day and a half and we're convinced they eliminate people they know because they say, 'Their gun is not the weapon I saw in the paper,'" he said.
Agents with the federal Bureau of Alcohol, Tobacco and Firearms apparently have been unable to determine what kind of weapon the sniper has been using, though they say ballistic and other evidence has linked nine of 12 attacks to the sniper.
Agents believe the other shootings are connected to the gunman, who has likely been using .223-caliber ammunition or rounds in the .22-caliber family.
"The type of rounds we're looking at here ... are fired by 30 types of firearms," said Michael R. Bouchard, who heads the ATF's Baltimore field office. "Within these 30-plus firearms, each manufacturer has a number of models that look the same."
Sun staff writer Michael James contributed to this article.