He didn't look like a hardened terrorist. A short, meek man with a neatly cropped beard and glasses, Moez Garsallaoui was shy and courteous. He served me and a CNN crew sweet Moroccan tea and north African cakes in the living room of the pinewood Swiss chalet he shared with his Belgian-Moroccan wife.

That was in 2006. Fast forward to the present: A posting on the Shumukh al-Islam Jihadist forum Monday said Garsallaoui had been killed in "a cowardly, treacherous raid" somewhere in the Afghanistan-Pakistan border region. He was 44.

In the intervening six years, he had become a jihadist of some standing, and may have influenced the young Frenchman who carried out a string of shootings in southwest France earlier this year.

"We received the painful news about the killing of another hero of the heroes of this Ummah, and one of its best," the posting by a militant calling himself Abu al-Laith al-Waziri stated, according to a translation by the SITE Intelligence Group.

A European counterterrorism official told CNN the claim appeared to be credible, but said confirmation of his death had not yet been received.

That cold afternoon in Switzerland, we had actually come to talk with Garsallaoui's wife. She was called Malika el Aroud, and was the widow of Abdessattar Dahmane, an al Qaeda operative who had killed the Northern Alliance leader Ahmed Shah Massoud in Afghanistan two days before 9/11.

Back then, she was attracting increasing scrutiny from European security agencies for running a pro-al Qaeda website and was earning a reputation as an "al Qaeda living legend" in radical circles because of a book she published about her time in Afghanistan.

Garsallaoui was tech savvy and showed us how he helped el Aroud administer the website from a computer in their bedroom. He was obviously in awe of his wife and her former husband, the al Qaeda hero.

After Garsallaoui traveled from Europe to the tribal areas of Pakistan in early 2008, the bookish Tunisian was transformed. Paramilitary training bulked up his physique and he became a significant operator in his own right amongst jihadists in the mountains of Waziristan.

In early 2008 he sent a picture of himself to his wife back in Belgium posing with a rocket-propelled-grenade launcher. "I saw the picture," el Aroud replied to him. "You are so beautiful." In another message -- intercepted by U.S. intelligence -- he told her he had killed several American soldiers in Afghanistan.

He appeared to be trying to prove to her that he was as worthy a Holy Warrior as her former husband.

In the months before he left for Pakistan, the couple had moved from Switzerland to Belgium, where they had worked to recruit militants to travel to Afghanistan to fight U.S. and NATO troops. Garsallaoui arranged for a group of Belgian and French militants to travel to Pakistan's tribal areas at the same time he did, and when they got there, he arranged for them to receive training from al Qaeda instructors, according to Belgian court documents.

One of the Belgian militants who traveled with Garsallaoui subsequently testified that Garsallaoui's marriage to Malika el Aroud had "opened doors" for him in Waziristan.

According to Belgian court documents, after his arrival, Garsallaoui formally joined al Qaeda by signing a membership document they presented him. He soon connected with senior al Qaeda operatives, including Abu Leith al-Libi, the group's Libyan military chief, and became acquainted with several al Qaeda recruits, including the American Bryant Neal Vinas.

He later told his wife that on January 31, 2008, he narrowly escaped being killed along with al-Libi in a drone strike after he spent the night at the Libyan's house.

'The archetype of the fanatical terrorist'

European counterterrorism officials believe that although he declared his allegiance to al Qaeda, he kept a significant amount of independence, moving between various groups in North and South Waziristan as a sort of jihadist freelancer.

In late 2008 several of the European militants who had traveled with Garsallaoui to Pakistan returned to Europe, sparking a terror alert in Belgium and a wave of arrests. Among those arrested was his wife, el Aroud, who was subsequently sentenced to eight years in prison. Garsallaoui was convicted in absentia, given the same length sentence, and he was made the subject of an Interpol Red Notice.

"He represents the archetype of the fanatical terrorist, disposed to the worst excesses to see his liberty-depriving philosophy succeed. Human life appears to have little value in his eyes," the Belgian judges who sentenced him concluded.

Several of Garsallaoui's proteges shared that fervor. One of the Belgium-based militants Garsallaoui brought to Pakistan -- Hicham Bouhali Zriouil, 33, a former Brussels taxi driver -- also developed close ties to al Qaeda's top leadership. Last year, senior Libyan al Qaeda operative Atiyah abd al-Rahman entrusted Zriouil with a mission to help set up al Qaeda's operations in Libya, a Western security official told CNN, but he was arrested in Syria before he made it there. Zriouil was subsequently extradited to Morocco and handed a 20-year prison sentence by a Moroccan court for terrorism-related offences.

In the spring of 2009, Garsallaoui posted a message on a jihadist forum claiming he was fighting beside elements of the Taliban, and making cross-border raids into Afghanistan from the tribal areas of Pakistan to target American troops. He delivered this message for Western counterterrorism agencies: "If you thought that you could pressure me to slow down through the arrest of my wife, you were wrong. ... Those who laugh last, laugh more."

Not much was heard from Garsallaoui in the years that followed apart from the occasional statement under one of his many aliases on jihadist forums, and a few online exchanges with Western journalists. Western intelligence agencies believed he was operating mainly in the tribal areas of Pakistan, and acting as a facilitator connecting European militants to al Qaeda and other affiliated jihadist groups. They believed that the rising toll of drone strikes had led to Garsallaoui playing an increasingly senior role.

In October 2011, Garsallaoui released a statement railing against democracy in his home country of Tunisia. Two months later, Garsallaoui again surfaced to post a message in support of attacks by a then-little-known al Qaeda affiliated jihadist group in Kazakhstan called Jund al Khilafah, or JaK, according to Western intelligence officials. CNN has seen the posting.

Suspected links to Toulouse shootings

Weeks later, Garsallaoui was in the spotlight of Western intelligence agencies like never before. In March 2012, a French-Algerian jihadist named Mohammed Merah carried out a series of shootings in southwest France that killed seven people, including three Jewish schoolchildren. Merah was eventually killed in a hail of gunfire during a siege at his apartment.