Man who boasted of global atrocities

Khalid Shaikh Mohammed, the man captured in a joint US-Pakistani operation yesterday morning, is believed to be one of al-Qa'ida's most senior operatives – possibly the most senior of all – and the mastermind behind the 11 September attacks in the US.

His capture is a tremendous feather in the cap of the Bush administration, which had offered up to $25m (£15m) for information leading to his arrest, and will no doubt be used to argue that the United States, contrary to the opinions of its own domestic critics, is perfectly capable of continuing the hunt for al-Qa'ida leaders while prosecuting a major war against Iraq.

Formally, Mohammed has been linked by prosecutors to the 1998 US embassy bombing in Nairobi in Kenya, and to the attack on a Tunisian synagogue last April in which 21 people died. But he himself pointed to his pivotal role on 11 September in an interview with al-Jazeera television last June. He said he was al-Qa'ida's military commander, and the man who first came up with the idea of flying commercial airliners into prominent public buildings.

He referred to the day of the attacks as "Holy Tuesday", saying they had been more than two and a half years in the planning.

Mohammed's apparent importance only came to light after the capture of another top al-Qa'ida operative, Abu Zubeida, in Pakistan a year ago. Indeed, it was largely Zubeida's information that led the US and Pakistan to the Karachi compound where Mohammed was living last September. Mohammed narrowly escaped capture on that occasion, but another key 11 September conspirator, Ramzi bin-al Shibh, was seized after a dramatic overnight shoot-out, and has been in US custody ever since.

If Mohammed is indeed as important as he and the Americans claim, then he also provides a vital link between al-Qa'ida and Ramzi Yousef, a convicted conspirator in the first attack on the World Trade Center in 1993, who later attempted to blow up a dozen airliners above the Pacific.

Several sources say Mohammed is Yousef's uncle. Both are apparently Pakistanis of Kuwaiti origin – although in Yousef's case there is some suspicion that he stole his identity from someone else entirely. Mohammed is also wanted in connection with the failed 1995 airliner plot. That makes him, according to US investigators, the key point of continuity between the two conspiracies to destroy Manhattan's twin towers.

US intelligence believes roughly a third of al-Qa'ida top leadership has either been captured or killed in the 17 months since the attacks on New York and Washington. That disruption, along with the destruction of al-Qa'ida's network of training camps in Afghanistan, has almost certainly helped thwart further attacks on US soil and diverted al-Qa'ida efforts towards so-called "soft" targets such as the Bali disco bombed last October or the Kenyan resort hotel struck one month later.

However, both Osama bin Laden and his number two, Ayman al-Zawahiri, remain unaccounted for and are presumed alive. Al-Qa'ida is believed to be regrouping in earnest along Pakistan's Northwest Frontier, on the border with Afghanistan, where it is effectively beyond the reach of either the Pakistani government or US forces. (Significantly, Mohammed was seized in Rawalpindi, near Islamabad, where the Pakistani government is more firmly in charge.)

US law enforcement agencies are also extremely worried about sleeper cells in place in American cities, which may be planning new attacks, possibly with biological, chemical or nuclear weapons. Domestically, the record of interdiction against al-Qa'ida is much more spotty, and many of those arrested have turned out to be far less significant than the government first claimed.

A second man arrested in Saturday's raid in Rawalpindi was also of Middle Eastern origin but has not been identified. A third man, a Pakistani, was identified as Abdul Qadoos. Pakistan's Interior Ministry spokesman Iftikar Ahmad said that Qadoos was linked to a terrorist organization, but he refused to identify it.

He said that Qadoos had been trained in Afghanistan. However, Pakistan's oldest and most organised religious group, Jamaat-e-Islami, said Qadoos was one of its members and that he had no links to al-Qa'ida or any other terrorist organisation.