The reported deaths of al-Qaeda's top two leaders in recent months have raised questions about the future strategy and strength of the terror network, already a shadow of the global force it was two decades ago.
The New York Times reported last week that al-Qaeda's deputy leader Abdullah Ahmad Abdullah, who went by the nom-de-guerre Abu Mohammed al-Masri, was secretly killed in Tehran in August by two Israeli operatives at Washington's behest.
Meanwhile, prominent experts on al-Qaeda have quoted sources as saying that Ayman al-Zawahiri, who succeeded Osama Bin Laden as the chief of the group, is also dead.
Iran has strongly denied the report over the killing of Abdullah, while al-Qaeda has not issued any confirmation of the purported death of al-Zawahiri through its usual media channels.
Yet the reports have come as questions grow over al-Qaeda's future intentions, with the network radically different from the franchise that spread fear around the world under the leadership of the charismatic Bin Laden.
'Very typical of AQ'
The killing of the Saudi in a US operation in Pakistan in 2011 left the group in the hands of al-Zawahiri, an Egyptian veteran of jihad and the key al-Qaeda ideologue, but without Bin Laden's ability to rally radicals around the world.
As early as August of last year, intelligence started emerging indicating that al-Zawahiri had a "heart complaint", a senior US official involved in international counter-terrorism efforts told CNN.
Hassan Hassan, director of the US-based Centre for Global Policy (CGP), said at the weekend that al-Zawahiri had died a month ago of natural causes.
And Rita Katz, director of the jihadist media monitor SITE, said unconfirmed reports were circulating that al-Zawahiri had died.
"It is very typical of AQ to not publish news about the death of its leaders in a timely manner," she said.
Nonetheless, this is not the first time there have been reports of al-Zawahiri's death, only for him to re-emerge on several occasions.
"Intelligence agencies believe he is very sick," said Barak Mendelsohn, associate professor at Haverford College and author of several books on al-Qaeda and jihadism.
"Ultimately, if it did not happen now, it will happen soon," he told AFP.
'Board of advisors'
If either or both men are dead, the group they have left behind can in no way be compared to the network which planned and carried out the September 11th attacks on the US, analysts say.
Its ideology has spawned several franchises across the world that bear its name, including in Africa's Sahel region, in Pakistan as well as in Somalia, Egypt and Yemen.
But it does not control their actions or the alliances that they may forge on a local level.
Mendelsohn said he expected al-Qaeda's leadership to act more along the lines of a "board of advisors" in the future.
"People will listen to AQ central leadership if they want to, not because they think they are bound to obey its view," he said.
No longer the supreme extremist group, al-Qaeda has seen other outfits grow and has sometimes clashed with them on the ground.
It has been overshadowed by the Islamic State of Iraq and Syria (ISIS) which sought to carve out a "caliphate" in Iraq and Syria and co-ordinated attacks in Europe.
ISIS's physical "caliphate" was dismantled in late 2017.
The key challenge of a new leader would be to retain the group's potency within this context.
Many analysts point to one key candidate -- Saif al-Adel, a former lieutenant-colonel in the Egyptian armed forces who joined the Egyptian jihadist movement in the 1980s.
He was arrested and then released, ending up in Afghanistan which was the base for Bin Laden and al-Zawahiri, and joining al-Qaeda.
According to the US-based Counter Extremism Project (CEP) think tank, he was arrested in Iran in 2003 and freed in 2015 in a prisoner exchange. He was still believed to be in Iran in 2018 as one of al-Zawahiri's key deputies.
"Al-Adel played a crucial role in building al-Qaeda's operational capabilities and quickly ascended the hierarchy," the CEP said.
Mendelsohn said al-Adel was a "big name" in the movement and "should be the next in line".
But he stressed that al-Adel, along with Abdullah, spent several years hiding in Iran, thus possibly staying away from al-Qaeda's new generation of leaders.
"I am not sure how strong his position is within al-Qaeda, especially now that the old generation, basically all the old guard, is dead."