(CNN) The reported killing of veteran al Qaeda figure Mokhtar Belmokhtar in a U.S. airstrike in Libya represents an extraordinary intelligence achievement against one of the most elusive and powerful jihadists in North Africa.
According to the Libyan interim government, Belmokhtar was killed in eastern Libya in an airstrike Saturday. In a statement issued late Sunday, the government said the strike targeted Belmokhtar "and a group of Libyans who are members of a terrorist organization in Eastern Libya." It said the operation "took place after consultations with the Libyan Government."
A U.S. official told CNN that Belmokhtar was "the intended target" of the operation, but no proof of his death has been provided by either government.
Both the United States and France have been hunting Belmokhtar for years. He was designated as a global terrorist by the United States 12 years ago, and there was a $5 million reward on offer for information about him.
If, as Libyan sources indicate, the strike was carried out close to the Mediterranean coast, it was several hundred miles away from Belmokhtar's home turf -- the vast and empty desert where Libya, Niger and Algeria meet. It's an area where for years Belmokhtar combined lucrative smuggling operations with ambitious terrorist attacks, becoming a leading figure in the often fractured group known as al Qaeda in the Islamic Maghreb (AQIM.)
But Belmokhtar is thought to have visited Libya before. In the aftermath of Moammar Gadhafi's overthrow in 2011, he established relationships with some of the more militant Libyan groups that were emerging. And he formed an elite unit called "Those Who Sign With Blood" specifically to attack Western interests in the Sahel and North Africa.
Sources in direct contact with Western intelligence agencies told CNN in the spring of 2013 that Belmokhtar had been in Libya for four months from December 2011. They say his visit was facilitated by the leader of a radical Islamist militia with influence in Benghazi and the East.
According to the sources, he met a Libyan veteran of jihad in Afghanistan who had set up camps near Sabha in southern Libya providing training for jihadists from Algeria, Morocco, Mauritania and Mali as well as Libyans and ethnic Tuaregs.
Belmokhtar made his intentions clear in a 28-minute video released in December 2012, warning Western governments: "This is a promise from us that we will fight you in the midst of your countries, and we will attack your interests."
A month later, his group - the Al-Mulathameen Brigade (The Brigade of the Masked Ones) -- launched its most ambitious attack yet against the In Amenas gas facility in eastern Algeria. Nearly forty workers, most of them foreigners, were killed in a three-day occupation of the plant. Western intelligence officials believe that camps in Libya may have been used by the group.
In Amenas is 50 kilometers from the Libyan border, and the group traveled through southern Libya on their way to the plant, according to counterterrorism officials.
A spokesman for Al-Mulathameen told Mauritanian news websites that the attack was in retaliation for Algeria permitting French overflights as part of its military intervention in Mali against AQIM, which at that point had taken over nearly half the country.
Some sources also connected Belmokhtar to the attack on the U.S. diplomatic compound and annex in Benghazi in September 2012, in which Ambassador Chris Stevens and three other Americans were killed.
Shortly after the attack, a phone call was placed from the area, according to two sources with high-level access to Western intelligence agencies who spoke to CNN early in 2013.
Whoever made the call was excited. "Mabruk, Mabruk!" he repeated, meaning "Congratulations" in Arabic, according to the sources. They told CNN the call was made to a senior figure in AQIM. There was no proof that the call was specifically about the attack, but the sources say that is the assumption among those with knowledge of the call.
One of the sources says the phone call was discovered when a Western intelligence service trawled through intercepts of communications made in the wake of the attack. That source told CNN that the call was made to Belmokhtar. The CIA had no comment on the alleged call.
Whether Belmokhtar was linked to the Benghazi attack or not, he was fast climbing the "most wanted" list. Federal prosecutors in the United States filed charges against him in 2013, including conspiracy, hostage-taking, kidnapping, providing material support to al Qaeda, and conspiring to use a weapon of mass destruction
Belmokhtar was a legendary figure among jihadists, but always his own man. Born in 1972, he grew up on the edge of the desert in southern Algeria and traveled to Afghanistan in 1991 to fight its then Communist government. He returned to Algeria as a hardened fighter with a new nickname "Belaouar" -- the "one-eyed" -- after he lost an eye in battle.
For a time in the 1990s he fought with the Armed Islamic Group (GIA) in its brutal campaign against the Algerian regime and civilians deemed to be its supporters -- and became the GIA commander for the Sahara. He then joined a group that was the forerunner of AQIM but frequently fell out with other leaders, who saw him as a loose cannon.
That was probably in part because of Belmokhtar's smuggling and kidnapping rackets, which netted his group tens of millions of dollars. He gained the nickname "Mr Marlboro" because of cigarette smuggling, and his group kidnapped a Canadian diplomat, Robert Fowler, in 2008, among many other foreign workers. It also moved drugs and illegal migrants and bought plenty of weapons and alliances with the proceeds.
His activities were too much for Abdelmalik Drukdal, the overall leader of AQIM, who is said to have demoted Belmokhtar in 2012 from his position as "Emir of the Sahel." Citing regional security officials, Agence France Presse reported at the time that Belmokhtar had been dismissed for "continued divisive activities, despite several warnings."
More recently, AQIM has further fractured over whether to swear allegiance to the Islamic State in Iraq and Syria (ISIS.) Belmokhtar's group had joined with two others to form an organization called al-Murabitoon, but when one faction declared for ISIS and Abu Bakr al Baghdadi last month, Belmokhtar quickly rejected the change.
"We confirm our commitment and loyalty to the pledge of allegiance to Sheikh Ayman al-Zawahiri," his group announced on May 14th.
Belmokhtar survived as long as he did because of the vast distances and empty landscapes of the Sahel: the rugged Algerian-Malian frontier is as long as the distance from New York to Chicago. He knew the region, its tracks and passes, intimately.
The French intervention in Mali appears to have pushed Belmokhtar north from his previous hunting grounds into Niger and southern Libya. He was able to take advantage of the complete collapse of government in Libya and the weapons bazaar that emerged there after Gadhafi's fall. But it seems that he was more frequently on the move, relying on a variety of Libyan allies. And that made him more vulnerable to being tracked and targeted.