Terror Detainee Is Seen as Leader in Plot by Al Qaeda
WASHINGTON, Aug. 5 - A terrorist suspect now in custody in Britain directed the surveillance of financial institutions in New York, New Jersey and Washington during 2000 and 2001 and prepared the detailed reports about them that have prompted fears of an attack, senior government officials said on Thursday.
The suspect, known as Abu Issa al-Hindi, was described by the officials as by far the most important Qaeda figure detained as part of an American-led effort to unravel the tangle of clues uncovered with the discovery in Pakistan of computer files containing the surveillance reports.
Mr. Hindi was described by a senior government official as "a key Al Qaeda operative in Great Britain,'' and was said to have been under surveillance by British authorities even before the computer files were discovered last week. The information drawn from those files served as "a catalytic event'' that provided the basis for his arrest on Tuesday, after the Central Intelligence Agency relayed information to its British counterparts.
A senior American official described Mr. Hindi as having been "intimately involved'' in producing, perhaps as the author, the detailed reconnaissance reports that described security measures, engineering features and potential vulnerabilities at five buildings, which have been identified by the Bush administration as potential targets of an attack.
Intelligence and law enforcement officials said it was not certain whether Mr. Hindi himself had traveled to the United States to take part in the surveillance operations. One law enforcement official said there was evidence that Mr. Hindi did conduct on-the-ground surveillance at the New York Stock Exchange and the Citigroup building in Manhattan and at the Prudential site in Newark.
At minimum, a senior counterterrorism official said, investigators have established that Mr. Hindi was a central planning chief for the reconnaissance effort, overseeing the surveillance studies in the United States and relaying reports and other information to Qaeda counterparts in Pakistan.
British officials remained tight-lipped on Thursday about the arrest of Mr. Hindi and 11 others being held with him on suspicion of involvement in terrorism. Under British law, the suspects may be detained for up to two more weeks without charges, and the British authorities have warned that speculation linking the arrests to operations in Pakistan could undermine the legal case against the suspects.
A senior counterterrorism said there had been several anxious days when the British authorities who had been trailing Mr. Hindi apparently lost sight of him after American intelligence learned of his significance.
Another man, Babar Ahmed, was arrested in central London on Thursday at the request of the United States, the police in London said, and American officials said he was being sought in connection with the operation that had been uncovered in Pakistan.
But a sealed warrant issued by the United States attorney's office in Connecticut at a time that has not been specified sought the extradition of Mr. Ahmed, 30, on unspecified charges in connection with his role in using American Web sites and e-mail to solicit money from Americans for terrorist causes from 1998 to last year.
It was not clear what evidence led the authorities to believe that he took part in the planning effort.
Intelligence and law-enforcement officials would not say whether they believed either of the arrests had disrupted an active plot to strike targets in the United States. But Mr. Hindi's arrest in particular was described as a major development in an effort to identify who conducted what American officials have described as the meticulous, professional studies of five financial buildings in the United States.
Mr. Hindi was tracked down after computer forensic specialists were dispatched to Pakistan to retrieve and decipher the information found on computers linked to two important suspects arrested there in recent weeks.
"Over the next 60 days, my guess is you're going to be seeing more of this kind of thing,'' a senior counterterrorism official said, referring to the arrests. "As we look more, we're going to find more.''
Even as the arrests took place, important questions remained. It is still not known whether the building surveys were part of a terrorist operation that was shelved or remains an active plot.
The authorities have theorized that the operation involved several people, some of whom probably lived in the United States for some time. But who they were, where they lived and whether they were in communication with senior Qaeda leaders, whose approval is usually required for major operations, is unknown.
Some senior American officials said they believed that Mr. Ahmed, like Mr. Hindi, had access to the computer records found in Pakistan.
The discovery of the reports, written in English in the period before the Sept. 11, 2001, attacks, came against a backdrop of more general, current intelligence pointing to a plot now under way. They were cited by the Bush administration as the most specific reason for elevating the terror threat alert last weekend.
A news conference to discuss Mr. Ahmed's arrest was scheduled for Friday in New Haven. American officials said on Thursday night that they believed he might be a relative of Muhammad Naeem Noor Khan, the 25-year-old Pakistani computer engineer at the center of the inquiry.
Mr. Khan, who is in Pakistani custody, led Pakistani investigators and the C.I.A. to the computers on which the surveillance reports were found, and has told Pakistani interrogators that he relayed messages to Qaeda figures outside the country.
American officials also said on Thursday that they now believed that Mr. Khan had played an operational role in gathering information about American targets, even beyond his previously disclosed role as a middleman in helping facilitate Qaeda communications. A fluent English speaker who traveled internationally, Mr. Khan spent time in Britain as recently as November 2002, the officials said.
The intensive search now under way in the United States, Britain and Pakistan for people connected to the surveillance reports has pointed to Mr. Hindi as the probable leader of a Qaeda cell in Britain that may have been involved in planning for a possible attack, the American officials said.
Mr. Hindi, who was one of 12 people arrested in Britain on Tuesday who are still in British custody, had earlier been identified as Abu Musa al-Hindi and Abu Eisa al-Hindi. The American officials who said they knew him as Abu Issa al-Hindi or Issa al-Hindi cautioned that all the names were believed to be aliases. They would not disclose his nationality, and details about his suspected role were being very closely held.
In Britain, officials remained reluctant to say anything more than that the arrest had taken place, and they hinted that they were still trying to determine who exactly Mr. Hindi might be. The British government has asked editors there to refrain from speculation in news accounts of the arrests.
The leader of the House of Commons, Peter Hain, told British Broadcasting Corporation radio that those detained in London on Tuesday had been "important arrests.'' But Mr. Hain declined to comment on reports in some publications that they had involved a plot against Heathrow Airport.
Officials in Pakistan have said that Mr. Khan has cooperated with his Pakistani interrogators, but they say they cannot be certain that his accounts have been accurate.
Patrick E. Tyler reported from London for this article, and Eric Lichtblau and Richard W. Stevenson from Washington.