Government officials are warning of a possible second wave of terrorist strikes in the United States as the FBI tries to determine whether some of the hijackers involved in last week's attacks were traveling under stolen identities.
MORE INVESTIGATIVE NEWS:
• FBI Uncertain of Hijackers' Identities • Terrorist Manhunt Continues • New Arrest Made • Possible Terrorist Stock Trading Probed
"We do expect more attacks," a senior Bush administration official said today. "We're at the point where anything is possible, but nothing can be predicted."
Law enforcement and intelligence sources tell ABCNEWS the FBI believes there is a strong possibility a network of terrorists is still in place in the United States preparing to launch additional attacks.
"We … have continuing concerns about the people responsible for Tuesday's attacks and information that does suggest they might have planned further attacks," said one senior intelligence official, who asked not to be identified. "But we don't have any intelligence that gives us specific dates or methods for those attacks."
Capitol Hill sources who have been briefed by the CIA tell ABCNEWS that intelligence points to an "umbrella plan" to destabilize the country.
Check back for continuous updates on the hunt for terrorists from ABCNEWS' worldwide investigative team.
• Possible Identity Crisis
There is now confusion about the real identities of the 19 men pegged by investigators as the terrorists who hijacked four planes on Sept. 11, crashing two into the World Trade Center, and a third into the Pentagon. The FBI acknowledged today some of the terrorists may have been traveling under aliases and stolen names.
"We have several hijackers whose identities were those of the names on the manifest; we have several others who are still in question," FBI Director Robert Mueller said while touring the site where the fourth hijacked plane, United Airlines Flight 93, crashed in Shanksville, Pa.
A Saudi Arabian official told ABCNEWS two of the men named as hijackers of the four planes that crashed have been confirmed to be alive and well.
The FBI has named Abdulaziz Al-Omari as one of the hijackers believed to have piloted American Airlines Flight 11 into the North Tower of the World Trade Center. But a Saudi man has reported to authorities that he is the real Al-Omari, claiming his passport was stolen in 1995 while he studied electrical engineering at the University of Denver.
The Saudis say they have confirmed Al-Omari left the United States on Sept. 3 and has proved that he was working in Riyadh when the attacks happened.
Newspapers in the Middle East also reported three others named as hijackers by the FBI — Saeed Al-Ghamdi, Mohald Al-Shehhi and Waleed Al-Shehhi — are alive.
• FBI Manhunt Continues
The FBI is continuing a nationwide manhunt for more than 200 people it believes may have ties to the hijackers. As many as 30 of the people on the bureau's "watch list" are believed to have had flight training.
ABCNEWS has learned that some of the men believed to have been trained as pilots had booked reservations on airline flights scheduled to take place in the days after last week's attacks — including flights coming out of Boston and San Antonio this coming weekend.
As he surveyed the Western Pennsylvania crash site, Attorney General John Ashcroft vowed to "disrupt, interrupt, stop, thwart, curtail the risk of further events like those events of Tuesday, September 11."
The attorney general said a day earlier he could not rule out that additional aircraft had been targeted for hijackings.
"We will leave no stone unturned to make sure that we do what we can to minimize the risk of reoccurrence," Ashcroft told reporters this afternoon.
Law enforcement officials said they believe the operations of the hijackers were based in Florida, Texas and New Jersey.
Many of the 30 or so individuals thought to have had pilot training are also known to have communicated with the hijackers.They are from a variety of locations within the United States and all of them are believed to still be in the country.
"This long list of people who had some kind of contact with the suicide hijackers of Sept. 11 … They may be part of a network," says ABCNEWS security consultant Vince Cannistraro. "That is a concern that is driving law enforcement in the investigation."
The FBI has obtained cell phone records and hundreds of e-mail messages exchanged by many of the 19 hijackers and their associates in the days and weeks leading up to the attacks.
• New Arrest Made
More than 115 people are now in federal custody in connection with the investigation, including several individuals who have been placed under arrest.
Most recently, a man identified as Nabil al Marabh was arrested Wednesday night at a liquor store where he worked the late shift in Burbank, Ill., just outside Chicago. Al Marabh had a commercial driver's license that allowed him to transport hazardous materials.
Sources tell ABCNEWS investigators believe al Marabh has ties to at least two of the suspected hijackers and the U.S.Customs Service has linked money transfers from Marabh to Raed Hijazi, a suspect in a failed plot to kill American tourists in Jordan during the 2000 millennium celebration.
Marabh, who has been in the United States for 11 years, sometimes working as a cab driver, has lived all over the country, including Tampa, Boston and Michigan. Marabh was convicted of stabbing his roommate in Boston and according to court records allegedly said, "If this wasn't America, I'd kill you."
When agents searched al Marabh's apartment in Detroit earlier this week, they found notes relating to an airport in Jordan, a diagram of an airport and fake identification badges.
Three Arab men were taken into custody at the residence and have been formally charged with the possession of false identification documents.
An investigation by a grand jury in White Plains, N.Y., has led to the detention of some 75 people for questioning, with five people under arrest as material witnesses. Among those arrested is an alleged associate of Osama bin Laden — the Afghanistan-based terrorist accused of masterminding last week's terror attacks — who was taken into custody Aug. 17 after workers at a Minnesota flight school raised suspicions about him.
In Hamburg, Germany, police have arrested two men linked to suspects in the hijackings.
Possible Terrorist Stock Trading Probed
New evidence has emerged of a possible effort by the terrorists who perpetrated last week's attacks to profit financially from the tragedy.
The Treasury Department, the Securities and Exchange Commission and a Chicago exchange have launched a major investigation into some suspicious and highly sophisticated stock trading just prior to the Sept. 11 terror attacks.
Investigators are probing highly unusual trading in "puts" — basically bets made by an investor that a stock's price will fall by a certain date.
The week before the attack, virtually unheard of numbers of puts were sold for United Airlines and American Airlines, which operated the four hijacked planes; Morgan Stanley, the investment bank which occupied more than 20 floors in the now-destroyed twin towers; and a number of other companies that were adversely affected by the tragedy and whose stocks plunged as a result.
"This would be one of the most extraordinary coincidences in the history of mankind if it was a coincidence," Dylan Ratigan of Bloomberg Business News said today on ABCNEWS' Good Morning America.
If it's not a coincidence and the money trail does lead to terrorist groups, they will have made a fortune.
"Millions of dollars, tens of millions of dollars on a bet that all told could be $600,000 turned into $10 million, $20 million," Ratigan said.
"This could very well be insider trading at the most horrific, most evil use you've ever seen in your entire life."
A senior intelligence official told ABCNEWS: "We still don't have any direct confirmation that [bin Laden] was involved in selling stocks short — yet."
The Treasury Department's Foreign Terrorist Asset Tracking Center has launched an effort to track financial transactions of members of bin Laden's terrorist network. The FBI today asked banks to check their records and report any transactions with any of the named terrorist suspects.