Did the Oklahoma bomber have help from al-Qa'ida's explosives expert?

Richard Clarke's book Against All Enemies has not just pushed the Bush administration deep on to the defensive over its approach to terrorism. It also pokes a stick into another hornet's nest by asking whether the 1995 Oklahoma City bombing was not in some way linked to al-Qa'ida.

Richard Clarke's book Against All Enemies has not just pushed the Bush administration deep on to the defensive over its approach to terrorism. It also pokes a stick into another hornet's nest by asking whether the 1995 Oklahoma City bombing was not in some way linked to al-Qa'ida.

Nobody, least of all Mr Clarke, is suggesting that al-Qa'ida carried out the bombing, which was pinned primarily on Timothy McVeigh, with help from his old army buddy Terry Nichols. But his book stirs up some troubling unanswered questions about Mr Nichols' many trips to the Philippines in the years preceding the bombing and raises the possibility that he received explosives training from Ramzi Yousef, the mastermind behind the first World Trade Centre bombing in 1993.

Mr Clarke notes that both Yousef and Nichols were in Cebu City, a hotbed of activity by the radical Filipino group Abu Sayyaf, on the same days, and that Nichols continued to make phone calls to Cebu for some time afterwards.

"Could the al-Qa'ida explosives expert have been introduced to the angry American who proclaimed his hatred for the US government?" Mr Clarke writes. "We do not know, despite some FBI investigation. We do know that Nichols's bombs did not work before his Philippine stay and were deadly when he returned."

The Nichols-Yousef connection was vigorously pursued at the time by McVeigh's trial lawyer, Stephen Jones, who was hoping to prove that Nichols was the true mastermind behind the bombing and that McVeigh was simply the fall guy. Evidence that has emerged since then actually tends to indicate the opposite - that Nichols eventually played a lesser role in the bombing, was not in Oklahoma City on the day, may not have been involved in assembling the bomb, and may not, as originally speculated, have carried out a crucial robbery that prosecutors say financed the operation.

None of that, however, diminishes the mystery of Nichols's activities in the Philippines or the possibility that US investigators missed a valuable opportunity to pursue leads that could have helped them foil the September 11 attacks, since at least two of the suicide-hijackers were based in the Philippines.

Mr Jones's biggest coup was to obtain evidence from a founding member of Abu Sayyaf, Edwin Angeles, who turned informer in February 1995 after being arrested in the Philippines. Mr Angeles told a local investigator working for Mr Jones that he had met an American nicknamed "The Farmer", who bore a strong physical resemblance to Nichols. Yousef was also at the meeting, Mr Angeles said.

Mr Jones saw similarities between the Oklahoma City bomb and the devices used in the 1993 World Trade Centre bombing and in the Khobar Towers bombing in Saudi Arabia in 1996. That led him to speculate that Nichols's true purpose in visiting the Philippines repeatedly during the early 1990s was to obtain explosives training.

Mr Jones pressed the judge in the McVeigh trial to admit Mr Angeles' evidence, but was turned down. Shortly afterwards, a Filipino prosecutor told a judge in Manila he had insufficient evidence to keep holding Mr Angeles and petitioned, successfully, for his release. Mr Angeles - who was beginning to give plenty of embarrassing information about officials in his own country as well as challenging the FBI's theory of the Oklahoma City bombing - has since disappeared.

Mr Clarke's book gives no indication of new information following this investigative dead-end. But Mr Jones has since argued that US investigators had no idea back in 1995 of how important the links were between the Philippines, Abu Sayyaf, al-Qa'ida and Osama bin Laden, and may have missed an opportunity to expose them before the African embassy bombings of 1998, let alone the September 11 attacks.

The questions about Nichols may yet get another airing as he is on trial again in Oklahoma, where state prosecutors hope to add to the work of their federal counterparts, who had Nichols jailed for life for the killing of federal agents, and secure a death penalty against him.

Nichols' story is that he was in Cebu City to visit the home of his mail-order bride. However, he spent a lot of time in the Philippines without her and after he returned to the US he made no fewer than 78 phone calls to Cebu City in the months immediately preceding the Oklahoma bombing.

Whether or not he played a lead role in the bombing, many questions remain about his Filipino connections.