Two days after his death, a video emerged Sunday of one of the Paris supermarket gunmen pledging allegiance to the Islamic State group, while his two fellow militants have claimed to be from al Qaeda, a fiercely rival extremist organisation.
That seeming contradiction has raised questions about the connections among the three French attackers, whether they acted with the direct involvement or knowledge of the networks, and whether their friendship allowed them to put aside the rift between the groups.
The Islamic State group does not cooperate with al Qaeda's militants and actually fights them for territory in a side conflict of Syria's civil war.
In video verified by the SITE Intelligence Group, Amedy Coulibaly said he had worked in coordination with Said and Cherif Kouachi, the "brothers from our team," who carried out the massacre at the satirical newspaper Charlie Hebdo on Wednesday.
"We did things a bit together and a bit apart, so that it'd have more impact," he said in fluent French, adding that he had helped the brothers financially with "a few thousand euros" for the operation. The video also showed him doing pushups, and featured automatic rifles, pistols and ammunition. He spoke beneath the black-and-white flag used by many Islamic militants.
Coulibaly explained why the publication and his target - the kosher supermarket - were selected.
"What we are doing is completely legitimate, given what they are doing," he said.
The video appeared Sunday on militant websites, and two men who dealt drugs with Coulibaly confirmed his identify to The Associated Press. Police said they were investigating the conditions under which the video was posted.
Prosecutors said Coulibaly killed four hostages Friday in the supermarket, killed a policewoman, and shot and wounded a jogger. He died when police stormed the market, just minutes after security forces killed the Kouachi brothers.
Survivors say the Charlie Hebdo attackers claimed they were from al Qaeda in Yemen, the group the US considers the most dangerous offshoot of that network.
But experts cast doubt over whether the attacks could have been coordinated by the rival groups. While Cherif Kouachi was convicted on terrorism charges in 2008, and his brother Said is believed to have trained and fought with al Qaeda forces while in Yemen, no evidence to date has emerged as to whether Coulibaly even went to Syria or Iraq, where IS holds territory. His widow was last traced to a town on the Turkey-Syria border a few days before the Paris attacks unfolded.
Since IS broke with al Qaeda last year, militants from the two groups have been locked in a bloody struggle in Iraq and Syria, where IS claims leadership of a universal caliphate of all Muslims and leadership of global jihad. The two groups have fought each other in battles that have left hundreds dead on both sides.
"It would be a massive surprise," said Peter Neumann, director of the International Centre for the Study of Radicalization at King's College London. "The idea that (the two groups) would consciously collaborate on operations abroad seems far-fetched."
"If anything, the most likely scenario is that there was some sort of playing off each other. Maybe - if there was synchronizing - it happened at the grassroots level," he said. Coulibaly's attack was far less professional, and appeared to be more spontaneous.
"He seems to be the prototype of the young, disengaged French Muslim who suffers from this sense of alienation, and then comes (to support an) ideology that makes him feel important, clear-cut and gives him purpose and orientation."
Timothy Holman, a researcher at the S Rajaratnam School of International Studies (RSIS) in Singapore, said the attackers represented who they wish to be perceived as representing, and had personal ties that likely surpassed the rivalries between the core extremist leadership abroad.
The Kouachis' link to Yemen also existed before the rift between IS and al Qaeda.
The friendship among the gunmen "predates their militant engagement, and they are fighting as much for each other in some ways as the groups," Holman said.
"In my opinion, their loyalty is first to their friends and family in the jihadist environment and then to the group. If Coulibaly's primary loyalty was to (IS), it is unlikely he would have acted at the same time as the Kouachi brothers," he added.
French police and judicial officials said they believed that while Coulibaly was committed to carrying out an attack, he was less of a strict ideologue or well-honed fighter than were the Kouachis - and could have found inspiration from either al Qaeda or IS.
In their internationally aimed propaganda magazines, both extremist groups promote the idea that overseas attacks need not have organisational links to the main leadership, and that "mujahedeen," or holy warriors, should take matters into their own hands.
Thousands of young people from Western Europe have headed to the war zones in Syria and Iraq to join extremists. Lawyers and family members of some of those who have gone say many have only a hazy sense of who will meet them when they arrive. But security officials fear that they will return home with new training in warfare, nursing old grievances.
While a member of al Qaeda's branch in Yemen said anonymously Friday that the group had directed the Charlie Hebdo attack, the group has not issued an official statement on the matter. Its senior cleric praised the operation but also stopped short of claiming responsibility directly.
Regardless, even if the al Qaeda group did not know about the attacks in advance, jihadi fighters in West Asia have a natural interest to claim such violence and present a unified front to adversaries - even if it sometimes goes against local positioning.
SITE reported late Sunday that Moktar Belmoktar, the head of the Mourabitoune group that split from al-Qaida's north Africa wing, had expressed praise in online jihadi forums for the Charlie Hebdo attack.
Aymenn al-Tamimi, a Britain-based expert on militant groups in Iraq and Syria, suggested the claims of loyalty to the rival jihadi groups aimed to stir up fears of militants uniting to fight the West.
Al Qaeda in Yemen may reject the Islamic State's declared caliphate, he said, "but they have stressed the necessity of supporting each other against the common enemy - which is, of course, the West."
Perhaps, al-Tamimi said, it was "to play on a bigger fear that the West has: that al-Qaida and the IS would come together for an attack," he added.