ROCKVILLE, Maryland, October 18 (IslamOnline & News Agencies) - U.S. Police shared "optimism," not progress, Friday, October 18, searching for an elusive sniper, as spy planes were readied to criss-cross Washington and outdoor events around the area are canceled. The investigation, meanwhile, were set to expand.

"I remain very optimistic," Montgomery County police chief Charles Moose told reporters. "I'm an optimistic person," Agence France-Presse (AFP) quoted Moose.

Police are grasping for clues after an eyewitness recanted his account of the most recent shooting, that of an FBI analyst Monday, October 14.

The shooter has been eerily silent since then, taking the longest respite so far in the shooting spree that has killed nine and wounded two others since October 2.

Moose said that one of the survivors, a 13-year-old boy in critical condition until Thursday, October 17, improved and may soon be able to speak about his ordeal.

Federal authorities are taking an increasing role in the investigation, committing two Army spy planes packed with surveillance gear to fly over Washington.

Moose said possible punishment of the false witness was not a priority for the sniper task force, but the matter had been turned over to a prosecutor in Fairfax, Virginia where FBI analyst Linda Frankin was killed outside a hardware store Monday.

Meanwhile, the search is being expanded internationally to probe the possibility that the attacks are tied to organized terrorist groups, according to law enforcement sources, reported The Washington Post.

FBI interrogators are questioning detainees at the U.S. military detention center in Guantanamo Bay, Cuba, about whether they know of any specific al-Qaeda plans to launch sniper attacks in the United States, the sources said.

However, a U.S. official speaking on condition of anonymity, told AFP that the U.S. has questioned suspected "unlawful combatants" held in Guantanamo Bay, Cuba but believes there is no connection to the sniper.

"There is no indication of that," the official said.

ABC News reported Friday, October 18, that al-Qaeda trained some of its snipers in using rifles in assassinations, based on videotapes obtained near Kabul by the network. In addition, ABC reported that a man named Nazir Trabelsi, arrested a year ago for allegedly plotting to blow up the U.S. Embassy in Paris, claimed that al-Qaeda had trained a three-man sniper team to kill U.S. senators at a distance of up to 250 meters (yards).

And in England, law enforcement officials reportedly earlier seized a manual on assassinations using firearms and believed to have been written by al-Qaeda.

U.S. authorities, however, continued to stress that no evidence emerged that would link the sniper to foreign or domestic terror groups. And a senior defense official said Thursday, October 17, that army surveillance aircraft, that were supposed to assist in the hunt, for the sniper had not arrived.

The witness's account led police to erroneously tell the public to watch for a cream-colored Chevy Astro van with a malfunctioning taillight and a ladder rack following the shooting death of Linda Franklin, the FBI analyst.

On Thursday, police cadets returned to the site of Monday's shooting and scoured the grass and pavement across Route 50 from the parking lot where Franklin was killed by a gunshot to the head. Sources said police searched the area Monday night and Tuesday before the rain came, but not as thoroughly as they did Thursday after they learned that the witness had provided false information, according to The Post.

The cadets did not recover a shell casing or other evidence, the sources said, and police now believe the sniper may have fired from about 100 yards away - more than twice the distance the witness claimed.

Detectives discovered that the witness's account was wrong when they checked it against versions given by others, said Lt. Amy Lubas of the Fairfax police. Police are now talking to still more witnesses who may have seen a white van fleeing the shooting, sources said.

The expansion of the probe followed a disappointing announcement by Fairfax County police Thursday that they discounted an account by a man who said he witnessed the latest shooting and given them a description of the shooter, his car and his gun.

Civil air controllers have begun coordinating with the U.S. Army possible flight patterns for the spy planes yet to be deployed.

The Army agreed to an FBI request to enlist the sophisticated RC-7 airplanes packed with surveillance equipment in the search. Because the U.S. military is prohibited from engaging in domestic law enforcement, an FBI agent will be aboard the planes and direct any relevant information to police on the ground.

Police hope the spy planes will help overcome the basic difficulty presented by the shooter's technique: striking seemingly random victims with a single shot, then retreating to strike again, somewhere in a geographical area that increases with each new attack.