When he served in the Afghan mountains as Osama bin Laden's bodyguard, Nasser al-Bahri said, he was known as "The Killer." Today, Bahri is a business consultant in Yemen who favors Western-style pinstriped shirts, crisp slacks and black loafers. But his ideas are still radical: Ask him whether jihadists should kill Americans on U.S. soil and he replies without hesitation, "America is a legitimate target." The arc of Bahri's life helps to explain why Yemen was an attractive place for Umar Farouk Abdulmutallab, the 23-year-old Nigerian who allegedly tried to bomb a Detroit-bound airliner on Christmas Day, to be indoctrinated into the Islamist world of jihad. Thousands like Bahri, who have returned from wars in Afghanistan, Iraq and other Muslim lands, are disengaged from the fight against the West, yet express sympathy for al-Qaeda's violent core philosophies. As the United States steps up its engagement here, it faces the delicate task of fighting terrorism without alienating Yemen's highly tribal and religiously conservative society. Like Pakistan and Afghanistan, Yemen has abundant weapons and men experienced in guerrilla warfare who resent U.S. policies and have tribal, social and inspirational ties to al-Qaeda. Many fear that such men could become perfect recruits, especially if anti-American sentiments grow or Yemen plunges deeper into chaos. "These people are already angry and many are unemployed," said Abdul-Ghani al-Iryani, a Yemeni political analyst. "The only option they will have if fighting starts is to join al-Qaeda. Where else will they go?" He added that Yemen is a place where "you cannot prevent contacts between young impressionable men and their jihadist heroes." Some of al-Qaeda's best-known figures, many with strong connections to bin Laden, live in this Middle Eastern nation led by a weak government and beset by multiple emergencies, from civil war to soaring poverty and dwindling oil reserves. Abdul Majid al-Zindani, bin Laden's former spiritual adviser, whom the United States has classified as a terrorist, is the most powerful religious figure here today. Senior Yemeni officials both fear him and seek his support. Nasser al-Wuhayshi -- bin Laden's former personal secretary -- is the leader of al-Qaeda in the Arabian Peninsula, which U.S. officials believe trained Abdulmutallab and equipped him with chemical explosives. U.S. and Yemeni investigators are also looking into a possible relationship between Abdulmutallab and Anwar al-Aulaqi, the extremist Yemeni American cleric who U.S. and Yemeni officials allege is one of the emerging spiritual leaders in al-Qaeda. Aulaqi has also been linked to the man charged with killing 13 people at Fort Hood, Tex., on Nov. 5. In an interview in a sunny room filled with computers at a business conference where he was working, Bakri, 37, said he has kept a relatively low profile in Yemen since 2002, when he was released from prison. He said Yemeni authorities held him for nearly two years without charge. He said he is no longer an al-Qaeda member and has no desire to return to a life of jihad. But he said he still admires bin Laden and his cause. "He is a man of substance," said Bahri, oval-faced and bald with piercing black eyes. "Whatever mistakes he has made, he has a very pure personality. He's simple, holy and sacred." 'I decided to join' Bahri, who was interviewed a few days before the failed bombing on Northwest Airlines Flight 253, was born in 1972 in Saudi Arabia to Yemeni parents. He grew up in the kingdom and earned a business degree in college. But like so many young Saudis, Bahri was deeply influenced by Sunni fundamentalist preachers and the Palestinian struggles against Israel. In 1993, he said, he traveled to Bosnia to join Muslims fighting the Serbs. Bahri was following a well-worn path. Thousands of Yemenis went to Afghanistan in the 1980s to fight the Soviets. They were welcomed back as heroes. President Ali Abdullah Saleh dispatched many to fight in the south during Yemen's 1994 civil war. Bahri said he had no desire to return to Saudi Arabia or Yemen. After Bosnia, he traveled on fake passports to Somalia and then Tajikistan, eventually arriving in 1996 in Jalalabad, Afghanistan. There, he heard bin Laden rail against U.S. actions in the Persian Gulf War and preach that Muslims needed to be unified against the West. "I decided to join," recalled Bahri, who was sent to a training camp in Khost province. A year later, he said, he took an oath of loyalty to bin Laden. One night, a group of armed defectors from the Taliban, the Islamic fundamentalist group that ruled Afghanistan, entered bin Laden's compound seeking to kill him. Bahri picked up his gun and shielded bin Laden. "After this, every time Osama bin Laden moved, he would say, 'Abu Jandal should be with us,' " recalled Bahri, using his nom de guerre. Nine months later, Bahri was shot in his left leg during a battle against Afghan rebels seeking to oust the Taliban. Bin Laden brought him food, changed his bandages and nursed him while he healed. "He would pour honey into my injury," Bahri recalled. Failed 'dialogue' In 2000, Bahri said, he had a falling-out with other al-Qaeda members and decided to visit Yemen with his Yemeni wife. Two months later, al-Qaeda militants bombed the USS Cole in the southern city of Aden, killing 17 American sailors. Bahri said he was not involved in the attack. But he said he was on a Yemeni security list of al-Qaeda operatives, so he went into hiding. When he tried to flee to Afghanistan, Yemeni intelligence agents captured him at the airport. Bahri said he was imprisoned without charges. Seven months later, after the Sept. 11, 2001, attacks, FBI agents arrived to interrogate him. In testimony before the U.S. Senate in May, former FBI agent Ali Soufan said interrogators obtained from Bahri "a treasure trove of highly significant actionable intelligence," including extensive information on bin Laden's terrorism network, its structure and its leadership. Bahri, he added, also provided "explicit details" of the Sept. 11 plot. Bahri said that although he fed the FBI lies, he believes his former al-Qaeda comrades view him as a traitor. After his prison term, including 13 months in solitary confinement, Bahri entered a prison rehabilitation program. Run by a prominent judge, Hamoud al-Hitar, it focused on using theological "arguing" as a tool of reform. It is now widely considered a failure. Bahri, along with two al-Qaeda militants convicted by the United States in the Cole bombings, were released after three sessions of "dialogue" over four months. "Hitar said he changed our minds," Bahri said. "But he did not." A latent danger After Bahri's release, employers were reluctant to hire him. He has had eight jobs in the past six years and earns a meager income. He said he once considered returning to Afghanistan but found it too risky. He was under surveillance by Yemeni intelligence and had to report to its officials every month. Those who know Bahri say he has given up militancy. Iryani, the political analyst, said Bahri has talked young Yemenis out of going to fight in Iraq. Iryani said former militants like Bahri need more support from the government. Without it, he said, "if they find the country to be under attack from outside, they will find a legitimate reason to go back to jihad."