Al Qaeda Sympathizers May Pose Sleeper Cell Threat

Documents: More Than 1,000 People With Possible Terror Ties in United States; Explosives Readily Accessible

WASHINGTON, July 13, 2005 —

ABC News has learned that there are hundreds of people in the United States with suspected ties to al Qaeda and whom the government fears could become part of terrorist sleeper cells in this country.

British investigators say the suspected suicide bombers responsible for last week's terror attacks in London behaved like a classic sleeper cell, raising concerns that more such attacks might be possible. Since the Sept. 11, 2001, terror attacks, the U.S. government has already arrested and jailed extremists who were believed to be involved in planning attacks.

"We've had sleeper cell cases," said Homeland Secretary Michael Chertoff. "We've often arrested people or brought those cases down early in the process. If you wait until people are doing operational planning, you are waiting too long."

In March, the FBI had identified more than 1,000 people suspected of being al Qaeda sympathizers in the United States, according to documents obtained by ABC News. At any given time, government sources say, the FBI has about 300 Islamist extremists who are under investigation or surveillance.

The government is trying to develop informants in certain mosques where they suspect there are radicals and is tailing or electronically eavesdropping on suspected extremists.

Tools of Terror Are Within Reach

For those willing to carry out attacks, there are plenty of explosives readily available.

From 2001 to 2004, more than 16,000 pounds of high explosives were stolen from construction sites and demolition companies, according to the Bureau of Alcohol, Tobacco and Firearms.

Equally as alarming, more than 60,000 pounds of blasting agents like ammonium nitrate -- the same chemical used in the Oklahoma City bombing -- were stolen, as well.

One of the explosive materials preferred by terrorists around the world is a homemade concoction called TATP. An ABC News team today bought three of the primary chemicals used to make TATP at local hardware and drug stores.

ABC News also found numerous Web sites where explosive chemicals can be easily ordered. With the right kind of explosives, experts say, a small amount can do incredible amounts of damage.

Security consultant Jeff Beatty, who has trained police departments across the country, says just 15 pounds of high explosive stored in a backpack can inflict major damage.

"The bombs in London were all believed to be under 10 pounds of explosives," he said. "That makes it difficult for the security forces because it is hard to detect."

The New York City Police Department created a special undercover unit to try find out how easy it would be to make a bomb.

"We've been able to go out and purchase the materials for a bomb, do it legally, and put it together and again detonate it," said New York City Police Commissioner Ray Kelly.

Building the bomb was easy to do and cheap, he says.

ABC News' Pierre Thomas filed this report for "World News Tonight."