Though the two sniper suspects had publicly expressed sympathy with the goals of the Sept. 11 hijackers, there was no evidence yesterday linking John Allen Muhammad and John Lee Malvo to any terrorist organizations, law enforcement and intelligence officials said.

The CIA searched its databases and foreign sources for any information about the two suspects and found none, said U.S. intelligence officials. An FBI spokesman in Washington said investigators had found neighbors of the two men in Washington state who had heard them say things "that were anti-American in nature and in sympathy with the September 11 group" -- but no ties to organized terror.

Still, authorities will be scrubbing both men's lives over the next several weeks, analyzing every trip they ever took, studying chance encounters and longtime relationships, law enforcement experts said. The FBI is looking into whether the two men had ties to Jamaat ul-Fuqra, a violent Muslim group with an American presence, sources familiar with the probe said.

Whether they establish links to terror groups or not, the Washington sniper has unquestionably terrorized the region, closing schools, shutting down miles of roadways, causing people to cower at shopping centers and gas stations. Therein lies a growing problem for government authorities: the distinction between terrorism and ordinary criminality is increasingly blurred.

"The notion of a coordinated cell has been supplanted by looser entities, and there's a conscious effort on the part of organizations like al Qaeda to inspire people to take up the cause without having them be part of any organizations," said Bruce Hoffman, a terrorism expert at the RAND Corp.

Police in Bellingham, Wash., where Muhammad and Malvo lived recently, said an acquaintance of the two reported three months ago that he was alarmed by their talk of wanting to kill police officers and seek the "downfall of America."

Muhammad, 41, is a convert to Islam and a member of the Nation of Islam, an American group headed by Louis Farrakhan, according to material contained in records of a 1995 child custody dispute. Neighbors in Tacoma, Wash., said that more recently he attended a mosque there that is not affiliated with the Nation of Islam. Malvo, 17, is a Jamaican immigrant. They have both lived in the Pacific Northwest, where two suspected al Qaeda cells were rounded up this year.

This month, federal prosecutors in Portland, Ore., obtained indictments of six people, including five U.S. citizens, on charges of conspiracy to make war against the United States and to support al Qaeda and the Taliban. The indictment charged that five of the men trained for war in the Portland area, then headed to Afghanistan to fight against the United States. A Portland woman was charged with wiring cash to her ex-husband to finance his journey.

In Seattle, American Muslim James Ujaama was arrested in July and accused of providing al Qaeda with training facilities, safe houses and computer services as part of a conspiracy to "murder and maim persons located outside the United States."

Malcolm Vance, a terrorism expert and security specialist who has analyzed the suspected terrorist cells in the Northwest, said they were largely made up of African American Muslims with links to Abu Hamza al-Masri, a radical Muslim cleric in London who has guided young congregants to al Qaeda.

Most of the Americans who traveled to Afghanistan for training in al Qaeda camps were African Americans who had converted to Islam, said Larry Johnson, a former CIA and State Department officer and counterterrorism expert.

But the alleged actions of those individuals may bear no relation to the actions and motivations of the Washington sniper.

"Even if this guy is a radical Black Muslim type, that doesn't make him al Qaeda or anything close to it," said an FBI official. "This was a freelance operation, and it's not clear that his sympathies were even a part of his motive."

Some investigators said the sniper may be more similar to the Egyptian national who shot five people, two fatally, at the El Al ticket counter at Los Angeles International Airport last July 4. The man, Hesham Mohamed Hadayet, was linked to a terrorist organization when he lived in Egypt, according to the government there, but he is not known to have had any terrorist associations during the years he spent in this country.

James Kallstrom, former head of the FBI's New York field office and a counterterrorism specialist, said authorities face an impossible situation.

Within the Muslim fundamentalist movement in the United States, he said, there may be a very small number of what he called hard-core terrorists, perhaps a few members of al Qaeda or Hezbollah. Then there is a second group, such as the six men from Lackawanna, N.Y., charged with providing al Qaeda material support by attending its training camps.

But a third group -- the "cheerleaders" -- are nearly impossible to track, Kallstrom said.

Law enforcement agencies do not have the resources to track and monitor such people, he said. And who can predict what will make someone snap and begin an intensely personal jihad?

"When does it change, and how will you know?" Kallstrom asked rhetorically. "You don't -- unless this person outwardly verbalized his hatred and witnesses hear that and told someone and law enforcement reacts with its scarce resources.

"And still, how do you predict the moment the person moves from fiery rhetoric to standing in his trunk and starting to shoot?"