Alleged key planner of the Sept. 11 attacks Ramzi Binalshibh, along with four other al Qaeda suspects, were flown out of Pakistan, the Pakistani government said Monday.
The five were arrested in raids last week in Karachi, marking a major success in the U.S.-led war against terrorism.
A search of the home of the five al Qaeda suspects turned up passports belonging to members of the family of Osama bin Laden, reports CBS News Correspondent Lara Logan.
Binalshibh, 30, is believed by the FBI to have been intended to be the 20th hijacker in the Sept. 11 attacks but was unable to enter the United States.
Instead, he provided logistical help to the operation and funneled money to his former roommate, Mohammed Atta, believed to have been the leader of the suicide hijackers.
Binalshibh boasted of his role in planning the Sept. 11 attacks during an interview in Karachi with Al-Jazeera television. The Arab satellite television station said the interview was filmed in June but aired only last week.
Earlier Monday, another government official, speaking on condition of anonymity, said police were investigating whether suspects arrested with Binalshibh were involved in the murder of Wall Street Journal reporter Daniel Pearl.
If a link were established, it would be the first evidence that al Qaeda may have been involved in Pearl's abduction and killing.
A senior U.S. official, who asked not to be identified, said the United States had taken control of Binalshib "several days" ago.
Interior Minister Moinuddin Haider said authorities now believe Binalshibh was the only high-profile al Qaeda figure arrested in the raids Tuesday and Wednesday. Officials had believed a second, unidentified al Qaeda leader was also caught.
Binalshibh was a member of the al Qaeda cell in Hamburg, Germany, that U.S. and German investigators believe planned and carried out the Sept. 11 attacks. During an interview broadcast by an Arabic language satellite station, Binalshibh boasted of his role in the attacks.
Meanwhile, in Buffalo, New York, a plea of innocent was entered in federal court for an American of Yemeni descent Monday, two days after five others arrested in western New York were charged with aiding terrorist organizations, federal officials said.
Mukhtar al-Bakri, the sixth suspect, was brought into court in handcuffs and shackles, and was granted a public defender. Al-Bakri, 22, was arrested in the Gulf emirate of Bahrain last week.
He told U.S. Magistrate H. Kenneth Schroeder he had been living in Bahrain since May and has been unemployed since May 2001. He last worked for Unity Wholesale in Lackawanna as a deliveryman earning $300 a week. One of the five men arrested over the weekend, Yahya Goba, also worked at Unity Wholesale.
Schroeder entered an innocent plea for al-Bakri and ordered him held until a bail hearing at 2:30 p.m. Wednesday with the other five suspects.
FBI agents recovered three weapons from the homes of the Buffalo suspects - a handgun, a rifle and a stun gun - but say they don't attach much significance to the discovery.
Instead, what is significant in agents' minds is a recent overseas telephone call between one of the young men and another suspect.
As CBS News Correspondent Jim Stewart reports, the call was placed from Bahrain to one of the Buffalo suspects by co-conspirator al-Bakri and was monitored by intelligence agents in Bahrain.
"Goodbye," al-Bakri told his friend over the phone, "You won't be hearing from me again." After his arrest, al-Bakri explained that he meant he was "getting married and dropping out of sight."
Intelligence agents, however, told CBS News they believe it was the farewell of a suicide bomber about to attack the U.S. base in Bahrain, which went on Delta Alert - its highest state of readiness - shortly after the intercept.
Al-Bakri's lawyer, John Molloy, meanwhile, questioned the strength of the government's case.
"The complaint charged is aiding a terrorist organization," he said. "I don't know what that means. The strength of their case might be impaired if there are no specific acts that they think are imminent."
Federal authorities acknowledged Saturday that they had no evidence of any imminent attacks planned by this cell.
Prosecutors say the men were members of a terror cell trained by Osama bin Laden's al Qaeda network and were under investigation even before the Sept. 11 attacks. They said the men had intensified their communications this month.
The men came home to Lackawanna, five miles south of Buffalo on the shore of Lake Erie, in June 2001. Federal agents said they had no information the cell was planning an attack in the United States.
The five men have been charged with providing material support and resources to foreign terrorist organizations. A plea of "not guilty" was entered on their behalf by the judge, who ordered the men jailed until a detention hearing Wednesday.
According to the criminal complaint, the five men — Shafal Mosed, 24; Faysal Galab, 26; Sahim Alwan, 29; Yasein Taher, 24; and Goba, 25 — live within a few blocks of each another in Lackawanna and trained together at a camp in Afghanistan.
In Singapore the government revealed Monday that they had arrested 21 people, most of whom belong to a regional Islamic group that authorities here have linked to al Qaeda.
All the suspects were arrested in August and are Singaporean citizens, according to media statement by the Ministry of Home Affairs.
The statement said most of the men were from Jemaah Islamiyah, a group that authorities in Singapore say had planned to attack U.S. interests there. Some of the men had received military training in Afghanistan and at a training camp of the Moro Islamic Liberation front in the southern Philippines, it said.
More than a dozen members of the group have already been arrested.
CBSNews.com Legal Analyst Andrew Cohen explains how the charge of providing "material support" to terrorists is getting a lot of use in today's environment.
This law, passed in the mid-1990s -- is shaping up to be the catch-all terror law that prosecutors hope will allow them across the country to indict and prosecutor alleged terrorists who haven't actually committed any actual acts of terrorism but who purportedly have trained for it. It's a government strategy that worked in the John Walker Lindh case and it's likely to work again here, writes Cohen.
John Walker Lindh was prosecuted for providing material support to terrorist organizations and a federal judge ruled in his case this spring that the statute applies when an individual participates in terrorist training, which is essentially the allegation here. So look for prosecutors to rely upon that Lindh ruling as they go forward with this case.
The phrase "material support" to terrorist organizations was initially thought to include financial support or support through the transporation of arms but the federal judge in the John Walker Lindh case late this spring gave the law a much broader interpretation to include providing someone's sweat equity, if you will, and that ruling is what prosecutors in the Buffalo case will rely upon, Cohen conludes.