If Al Qaeda strikes the West in the coming months, it's likely the mastermind will be a stocky Egyptian explosives expert with two missing fingers.
His alias is Abu Ubaida al Masri. Hardly anyone has heard of him outside a select circle of anti-terrorism officials and Islamic militants. But as chief of external operations for Al Qaeda, investigators say, he has one of the most dangerous -- and endangered -- jobs in international terrorism.
He has overseen the major plots that the network needs to stay viable, investigators say: the London transportation bombings in 2005, a foiled transatlantic "spectacular" aimed at U.S.-bound planes in 2006, and an aborted plot in this serene Scandinavian capital last fall.
But pursuers have captured or killed his predecessors and have been gunning for him. He prowls Pakistani badlands one step ahead of satellites and security forces.
Although periodic reports of his death have proved false, rumors resurfaced after recent American airstrikes. Asked whether Masri is alive, a Western anti-terrorism official said, "It's a question mark."
Masri himself can be described that way. Authorities know only bits and pieces of his biography. They know his face, having identified an unreleased photo, but not his real name.
"He is considered capable and dangerous," said a British official, who like others in this report declined to be identified. "He is not at the very top of Al Qaeda, but has been part of the core circle for a long time. He is someone who has emerged and grabbed our attention as others were caught or eliminated in the last couple of years. Perhaps he rose faster than he would have otherwise."
The Times has charted Masri's rise in interviews with anti-terrorism officials and experts from Europe, the United States and the Middle East, and a review of case files and academic and intelligence reports. The stories of man and network intertwine, revealing the dangers and vulnerabilities of both.
Masri's emergence reflects Al Qaeda's resilient, hydra-like structure. As leaders fall, mid-level chiefs step up, shifting tactics and targets with determination and innovation.
But Al Qaeda seems diminished despite insistent propaganda and an onslaught of violence in Iraq, South Asia and North Africa. The network has not pulled off an attack in the West since 2005.
"We have to be careful not to fall prey to our fears," said a senior British anti-terrorism official. "The language of 2001, 2002, gave an inflated view of Al Qaeda's size and structure. It's not the Red Army, it's not even the Irish Republican Army. . . . There have been advances by AQ at the ideological level, it has spawned franchises, but don't lose sight of the operational setbacks that AQ has suffered."
The plots attributed to Masri were ambitious, but authorities infiltrated two cells long before they could strike. Some trainees seemed more fierce than talented. And the number of seasoned field commanders dwindles, former CIA officer Marc Sageman said in an interview.
"Al Qaeda's bench is shrinking," Sageman writes in his latest book, "Leaderless Jihad." "Yes, there are trained and still quite competent terrorist trainers around, and they are more visible in Waziristan [in Pakistan], but the long-term prospect of Al Qaeda central in the Afghan-Pakistani theater is diminishing."
But other experts see signs of resurgence. Last year, U.S. spy agencies warned that Al Qaeda had "protected or regenerated" its leadership and ability to attack the United States by carving out a haven in Pakistani tribal areas.
Masri is in his mid-40s, according to an Italian translation of a German investigative file. His nom de guerre means "The Egyptian Father of Ubaida." Little is known about his youth. He belongs to a generation of Egyptians who have dominated Al Qaeda since they fought the Soviets in Afghanistan, officials say.
Masri followed the classic itinerary after Afghanistan, officials say. He fought in Bosnia-Herzegovina in the early 1990s, went on to Chechnya and was wounded, according to the Italian file. He lost two fingers -- a common disfigurement suffered by Al Qaeda veterans from combat or explosives. Masri also spent time in Britain, according to the file. In 1995, he surfaced in Munich, Germany, under an alias and requested asylum. His associates there included a Moroccan computer science student who married the daughter of Ayman Zawahiri, Osama bin Laden's deputy, and Jordanian operatives who led a 2002 plot for shooting attacks on Jews.
In 1999, authorities rejected Masri's asylum claim and jailed him pending deportation. But he was released instead for reasons that are unclear.
Tanned and muscular
By 2000 he was back in Afghanistan serving as an instructor at a training camp near Kabul, where he taught about explosives, artillery and topography, according to the file. Shadi Abdalla, a former Bin Laden bodyguard, described him in later testimony as 5 foot 7, muscular and tanned, with graying black hair and a graying beard.
During the U.S.-led military operation in Afghanistan in late 2001, Masri fought in the 055 Brigade, a paramilitary unit that took heavy casualties covering Bin Laden's escape into Pakistan, according to Rohan Gunaratna, author of "Inside Al Qaeda." Holed up in the border region, the survivors split into two wings, he said. Internal operations ran combat in Pakistan and Afghanistan, where Masri helped the Taliban regroup. External operations oversaw attacks elsewhere.
After the capture in 2003 of the manically prolific Khalid Shaikh Mohammed, the self-proclaimed Sept. 11 mastermind, Masri's duties shifted. He joined a group of chiefs who tried to keep targeting the West, mainly Britain.
They succeeded on July 7, 2005, killing 52 people in synchronized public transportation bombings in London. The lead bombers were groomed in Pakistan by Abdul Hadi, a former Iraqi military officer, according to officials and court testimony. Masri's name emerged as a planner working with him.
"He's considered a player," a U.S. anti-terrorism official said. "He comes up on the radar screen a few months after July 2005."
In January 2006, an airstrike killed 18 people in the Bajaur region of Pakistan. The press reported, inaccurately, that Masri and three other leaders died in the rubble.
The plane plan
Masri had embarked on his biggest task yet: a mega-project intended to match the carnage of the Sept. 11 attacks by blowing up airplanes en route from Britain to the United States. Half a dozen British militants traveled to Pakistan for training.
"He was involved in recruiting, overseeing the lesson plan, so to speak," the U.S. anti-terrorism official said.
The innovative techniques required special instruction. Masri envisioned his operatives injecting the liquid explosives, a highly concentrated hydrogen peroxide mix, with a syringe into the false bottoms of innocuous containers such as sports drinks, sneaking the components aboard and assembling bombs after takeoff.
"The airline plot is his thing," a Western intelligence official said. "And it is a major plot."
Investigators think only one or two trainees had contact with Masri. Trainees had autonomy to instruct and supervise a dozen fellow militants back in Britain, officials say. In turn, investigators believe Masri got direction from his bosses, who often communicate with the command structure through messengers.
"We have patchy intelligence on the relationship and structure between external operations figures and Zawahiri and Bin Laden," the senior British official said. "In the really big plots, we think they played a role."
Investigators monitored the plotters for months, managing to film inside their London safe house. In August 2006, police rounded them up. The attack was weeks away and would have targeted five planes, the U.S. anti-terrorism official said.
Three months later, Pakistani helicopter gunships blew up a remote madrasa, killing about 80 people but missing Masri, officials say. In late 2006, however, Israeli, Turkish and U.S. spies teamed up to capture Hadi, the former Iraqi military officer, in Turkey as he was en route to Iraq to improve relations with the Al Qaeda offshoot there, officials say.
Masri assumed more control. He allegedly turned his aim to another part of Europe he knows. Last spring, he taught bomb-making in compounds in North Waziristan to aspiring suicide attackers, including a 21-year-old Pakistani living in Denmark and a 45-year-old Pakistani-German, according to U.S. and European officials.
A U.S. anti-terrorism source sees Masri's role as a symptom of decline. "The fact he trained them himself shows you some of the limitations of the network," the source said.
In any case, Masri's pupils apparently displayed more fervor than stealth. Aided by U.S. intercepts of communications to Pakistan, Danish police put the 21-year-old under surveillance along with his associates, one of whom had been in Pakistan at the same time. As in London, police got deep inside the alleged cell, U.S. and European officials say.
Police installed clandestine cameras and microphones in the 21-year-old's apartment in a scruffy area that mixes immigrant families and young Danes. In early September, the cameras filmed the 21-year-old and an Afghan suspect as they sang militant songs and mixed TATP, the explosive used in the London attacks. The two even conducted tests of detonators in a vestibule, officials say.
Two days later, police jailed them. Last week, prosecutors filed formal charges against three suspects. Seven others remain under investigation. The alleged target has not been disclosed. Al Qaeda has threatened Denmark because of the publication here of cartoons seen as insulting to the prophet Muhammad.
In the cross hairs
Masri's ongoing contact with foreign operatives put him in the cross hairs. U.S. forces have unleashed a flurry of airstrikes in Waziristan this year, killing a top Libyan chief, Abu Laith al Libi, and other Arab militants in late January.
Recent intelligence suggests that Masri died too, officials say. But they say they have no confirmation, no Internet eulogies of the kind that celebrated Libi.
Cultivating the art of survival through anonymity, Masri may have beaten the odds once again. Or it may be that, for strategic reasons, both sides want to keep his fate ambiguous as a successor emerges.
The external operations chief, the senior British official said, has "the job with the lowest life expectancy in international politics."
Special correspondent Dirk Laabs in Hamburg, Germany, and Noha El-Hennawy of The Times' Cairo Bureau contributed to this report.