PARIS -- His entourage calls him "the Prince," and after the militant Islamist takeover of a town in northern Mali last year, he liked to go down to the river and watch the sunset, surrounded by armed bodyguards.
Others call him "Laaouar," or the One-Eyed, after he lost an eye to shrapnel; some call him "Mr. Marlboro" for the cigarette-smuggling monopoly he created across the Sahel region to finance his jihad. And French intelligence officials called him "the Uncatchable" because he escaped after apparently being involved in a series of kidnappings in 2003 that captured 32 European tourists, an undertaking which is thought to have earned him millions of dollars in ransoms.
Mokhtar Belmokhtar, 40, born in the Algerian desert city of Ghardaïa, 350 miles south of Algiers, is now being called the mastermind of the hostage crisis at an internationally run natural-gas facility in eastern Algeria.
Algerian officials say he mounted the assault and the mass abduction of foreigners; his spokesmen say the raid is in reprisal for the French intervention in Mali and for Algeria's support for the French war against Islamist militants in the Sahel.
Mr. Belmokhtar has been active in politics, moneymaking and fighting for decades in the Sahel, which includes Mali, Mauritania and Niger and is one of the poorest regions in the world. But through this single action, one of the most brazen kidnappings in years, he has suddenly become one of the best-known figures associated with the Islamist militancy sweeping the region and agitating capitals around the world.
The 1989 killing in Pakistan of Abdullah Yusuf Azzam, a Palestinian considered the "father of global jihad" and a mentor of Osama bin Laden, prompted Mr. Belmokhtar to seek to avenge Mr. Azzam's death, he has said in interviews. At 19 he traveled to Afghanistan for training with Al Qaeda, and has claimed in interviews to have made contact with other jihadi luminaries like Abu Qatada and Abu Muhammad al-Maqdisi, according to a 2009 Jamestown Foundation study. Bin Laden made contact with him, through emissaries, in the early 2000s, according to Djallil Lounnas, who teaches at Al Akhawayn University in Morocco.
Mr. Belmokhtar later named a son Osama, after Bin Laden, and inserted himself into local populations in the southern Algerian and northern Malian desert by marrying the daughter of a prominent Arab leader from Timbuktu, Mali. He is also said to have shared the riches of his lucrative activities with the impoverished local population, Mr. Lounnas has written.
Mr. Belmokhtar, described as taciturn, watchful and wary by a Malian journalist, Malick Aliou Maïga, who met him last summer, was one of the most experienced of the leaders of what became Al Qaeda in the Islamic Maghreb until he broke with the group last year to form his own organization, the Signed-in-Blood Battalion, sometimes translated as the Signatories for Blood. Occasionally using the alias Khaled Abu Abass, he is thought to have based himself in Gao, Mali, which has seen heavy bombing by French warplanes.
It was not clear whether Mr. Belmokhtar was at the scene or commanding the operation from afar.
There are stories that he lost his eye fighting in Afghanistan, but others say he lost it fighting Algerian government troops after he returned to Algeria in 1993. The country was being ripped apart by civil war at the time, after the government annulled 1992 elections that were about to be won by an Islamist party. Mr. Belmokhtar has been a wanted man in Algeria since that time and condemned to death several times by Algerian courts.
Mr. Belmokhtar was falsely reported to have been killed in 1999. Nearly a decade later, the Salafist Group for Preaching and Combat, which he joined, adopted the jihadist ideology of Bin Laden and renamed itself Al Qaeda in the Islamic Maghreb. Mr. Belmokhtar is considered to have been a key intermediary with Al Qaeda and a well-known supplier of weapons and matériel in the Sahara.
But he clearly does not share authority easily, and left or was removed from his post as commander of a battalion in Mali last October, reportedly for "straying from the right path," according to a Malian official, quoting the leader of Al Qaeda in the Islamic Maghreb, Abdelmalek Droukdel.
The dispute was about Mr. Belmokhtar's return to smuggling and trafficking. Dominique Thomas, a specialist in radical Islam, told Le Monde that Mr. Belmokhtar's activities ran counter to the group's official line, which presents itself as entirely virtuous.
Mr. Belmokhtar then founded his new group, which he allied with the Movement for Oneness and Jihad in West Africa, another Islamist group that had broken off from Al Qaeda.
Some suggest that his expertise has been more in criminal activities than in holy warfare. Kidnapping and smuggling -- of cigarettes, stolen cars, arms and drugs -- have been his specialties in the vast and largely lawless border regions. He was said to be central to hostage-takings and subsequent negotiations for their release in 2003, 2008 and 2009.
Robert R. Fowler, a former Canadian diplomat and a United Nations special envoy to Niger, was kidnapped by Mr. Belmokhtar's brigade in late 2008 and met with him several times.
"He's a fairly slight, very serious, very confident-looking guy who moves with quiet authority," Mr. Fowler said in a telephone interview from Canada. "He's clearly been in the business of being a terrorist and surviving for a long time. I was always impressed by the quiet authority he exhibited."
Mr. Maïga, the Malian journalist, recalled seeing Mr. Belmokhtar, dressed in black and wearing a turban that descended over his eye, leaving a hospital in Gao with his entourage. He called out to him, and a bodyguard quickly interposed himself: "You must not," the bodyguard warned. "That is the Prince."
Subsequently, Mr. Maïga recalled seeing Mr. Belmokhtar seated on the beach by the river at Gao, surrounded by bodyguards. "He was saying nothing. He has a fixed stare. He doesn't trust people."
Mr. Maïga and others say locals regard him with both respect and fear.
In an interview with the Mauritanian news agency Alakhbar in Gao in November, Mr. Belmokhtar said he respected "the clearly expressed choice" of the people of northern Mali "to apply Islamic Shariah law." He warned against foreign interference, saying that any country that did so "would be considered as an oppressor and aggressor who is attacking a Muslim people applying Shariah on its territory."
Mr. Belmokhtar was already scheduled to be tried again in absentia by the Algiers criminal tribunal starting next Monday, on charges that include supplying weapons for attacks on Algerian soil. Planned targets were said to include pipelines and oil company installations in southern Mali.
Steven Erlanger reported from Paris, and Adam Nossiter from Bamako, Mali. Harvey Morris contributed reporting from London, and Eric Schmitt from Washington.
This article originally appeared in The New York Times.