By The New York Times
In the years before his death, Osama bin Laden spent his days behind the walls of his compound in Pakistan, fretting about his son living thousands of miles away.
He penned letter after letter, describing the curriculum that the son, Hamza bin Laden, then 23, should study, the qualities he should cultivate and the safety measures he should follow. In one, he advised his son, who was just 13 when he saw his father for the last time, not to leave his house.
In another, he discussed whether the young man could rejoin him in Pakistan, advising him to travel on a cloudy day when it would be harder for a drone to track him. He devised a complicated security protocol, calling for the son to switch cars inside a tunnel in order to fool overhead surveillance.
The care he showed was not just that of a father for a son. It appears to have also been an attempt by the world’s most hunted terrorist to secure his legacy.
Analysts believe that since at least 2010, Al Qaeda was secretly grooming Hamza bin Laden to take over the organization, a move that now appears to have been foiled. According to three American officials, the younger bin Laden was killed during the first two years of the Trump administration.
If confirmed, his death represents another blow to Al Qaeda, whose ranks were hollowed out by relentless American attacks and by the rise of the Islamic State, also known as ISIS. The older terrorist network has struggled to appeal to a younger generation of recruits, who were lured to ISIS by slick videos shot on drones and GoPros when Al Qaeda was still issuing hourlong lectures by aging leaders staring at camcorders.
The younger bin Laden was supposed to solve several of Al Qaeda’s most pressing management issues: No older than 30, he was almost four decades younger than Ayman al-Zawahri, the group’s current leader, who has been vilified by ISIS as an old-fashioned and out-of-touch manager.
Because he carries the most famous name in terrorism, the younger bin Laden is able to draw on the devotion that jihadists around the world feel for his father. For these reasons, Al Qaeda hoped that Hamza bin Laden would be a unifier, appealing not just to the group’s base but also to the recruits it lost to ISIS, many of whom are at a crossroads after the ISIS’s loss of territory in Iraq and Syria.
“If it’s true that he is dead, then Al Qaeda has lost its future because Hamza was the future of Al Qaeda,” said the former F.B.I. agent and counterterrorism expert Ali Soufan, who sounded a note of caution because it is unusual for Al Qaeda not to announce such a death.
“He was being prepared to lead the organization, and it’s very obvious from his statements that his focus was to bring back his dad’s message,” said Mr. Soufan, who is the author of a profile of Hamza bin Laden calling him “Al Qaeda’s leader in waiting.”
But the circumstances of his death, like much of his life, remain murky. The United States government does not know precisely how he died.
An American airstrike in the Afghanistan-Pakistan region, in May or June 2017, targeted Mr. bin Laden. It killed his son but not him, according to current and former American officials, who spoke on condition of anonymity to discuss the circumstances of Mr. bin Laden’s death, which remain a closely held secret.
The officials said Mr. bin Laden may have been wounded in the strike.
A third American official said that Mr. bin Laden died in December 2017 after being wounded in an airstrike.
By February, when the State Department put a $1 million reward for information on his whereabouts, intelligence officials believed he was dead. Officials now have the high confidence that he is dead even if the exact circumstances of his death remain unknown.
Mr. bin Laden had been mistakenly pronounced dead before, when officials thought he had died in the SEAL raid to kill his father.
Al Qaeda, usually forthcoming in announcing the death of a leader as a martyr, has issued no confirmation or denial. One of the American officials said Al Qaeda had kept the death secret out of concern that the news would hurt its fund-raising.
Mr. bin Laden was thought to have been living along the Afghan-Pakistani border but there were only vague reports about possible sightings.
“Our intelligence reports showed there was a Hamza here, but we didn’t know for sure,” said Mohammad Ismail, the governor of Want Waigal, a mountainous district in eastern Afghanistan near the Pakistani border. “Some would say he was a Pakistani and some would say he was an Arab.”
Letters to and from his father — found by the Navy SEAL team that killed the elder bin Laden and were later declassified — indicate that he was living in Iran for several years, including in 2009 and 2010. Initially he lived in a Qaeda safehouse before being imprisoned in a military camp, Mr. Soufan said.
Mr. bin Laden has not been as elusive in his public statements. After his father was killed in Abbottabad, Pakistan, in 2011, he promised vengeance, calling for attacks on Western capitals and warning Americans that they would be “targeted in the United States and abroad,” according to the State Department.
In audio recordings released by Al Qaeda beginning in 2015, he called for the overthrow of the Saudi monarchy and urged Syrian jihadi groups to unite to liberate the Palestinians. In one, he advised prospective jihadis to “follow in the footsteps of martyrdom-seekers before,” according to analysis from the Long War Journal, a publication from the Foundation for Defense of Democracies, a Washington-based policy institute.
Hamza bin Laden was only 13 when his father walked him and his brothers to the base of a mountain in Afghanistan and said goodbye for the last time. It was 2001 and planes piloted by Qaeda operatives had just slammed into the World Trade Center and the Pentagon, and another hijacked plane had been foiled on its way to Washington.
The terrorist leader knew that retaliation was not far behind and made arrangements to send his boys away. He handed each of them a set of Muslim prayer beads, reminding them to seek strength in their faith.
“You bid us farewell and we left, and it was as if we pulled out our livers and left them there,” Hamza bin Laden wrote in a letter addressed to “my beloved father” years later.
The identical gifts to his sons suggest that the senior bin Laden intended to be equal in his affection. But chroniclers of the family say that it was not long before it became clear that he had a special relationship with Hamza, the only son of Khairia Sabar, a highly educated Saudi woman who became Osama bin Laden’s favorite wife.
The two married when she was in her mid-30s, and they struggled to conceive. She endured repeated miscarriages before giving birth to Hamza in 1989, according to Mr. Soufan’s profile. Hamza was believed to have been born in Jidda, Saudi Arabia, one of 23 children his father would eventually have, according to Western intelligence agencies.
His mother became a partner in her husband’s project of global jihad, even helping him draft the speech he planned to deliver on the 10th anniversary of the Sept. 11 attack, according to Mr. Soufan.
“What Hamza had going for him was his mother,” said Lawrence Wright, who tracked the family’s history in his book “The Looming Tower.” “His mother was Bin Laden’s favorite wife, and by a long shot. She was very intelligent and very well educated and claimed descent through the prophet.”
That lineage became even more important after 2014, when ISIS declared its caliphate and appointed a caliph. Only men who are descended from the family of the Prophet Muhammad are eligible to be named caliph.
Hamza, Mr. Wright said, “is the only one of Bin Laden’s children who can make that claim and I think that is an asset.”
When Hamza was 2, his father moved from Afghanistan to Sudan. He was there until the age of 7, when the Sudanese government gave in to international pressure and expelled him. He and his followers returned to Afghanistan where they sought refuge with the Taliban and lived in a complex of concrete huts, lacking plumbing, electricity and even doors.
After the 2001 attacks, he was spirited over the mountains into Pakistan, before seeking refuge in Iran, where he initially lived in a Qaeda safe house, according to Mr. Soufan. He and his mother were eventually arrested by the Iranian authorities and incarcerated in a military camp.
As Hamza grew older, he sought no special treatment within the group as Osama bin Laden’s son.
“He does not want to be treated with favoritism because he is the son of ‘someone,’” according to a 2010 letter from an aide to the elder bin Laden. “I promised him to plan some safe training for him: firing arms and with various weapons.”
Hamza bin Laden married a daughter of a senior Qaeda leader, Abdullah Ahmed Abdullah, a wedding that was recorded on video found in the Abbottabad compound.
Thomas Joscelyn, a senior fellow with the Foundation for Defense of Democracies who has been studying Al Qaeda for years, said that the younger bin Laden’s role in the organization was opaque.
“We don’t actually know what his real role was within Al Qaeda,” he said. “We know Al Qaeda was marketing him as a voice for a younger generation. You could see that when they would put out these audio messages from him.”
Mr. Joscelyn cited evidence in the older bin Laden’s personal files that Hamza had received elite training but that Osama bin Laden preferred that his son not take on a military role.
Hamza’s own ambitions, based on his audio recordings and letters to his father, indicated a desire to take an active role in Al Qaeda.
“My beloved father, I was separated from you when I was a small child, not yet 13, but I am older now, and have attained manhood,” he wrote in the 2009 letter.
“But what truly makes me sad,” he added, “is the mujahedeen legions have marched and I have not joined them.”
In 2017, the United States officially listed him as a global terrorist. In a letter published by Al Qaeda the same year, Hamza bin Laden said his 12-year-old son had been killed, according to the SITE Intelligence Group. The circumstances were unclear.
Three Iraqi intelligence officials said there was a failed attempt to kill Hamza bin Laden that year.
In February, the State Department announced a $1 million reward for information about his whereabouts, and Saudi Arabia revoked his citizenship. According to the American officials, he was already dead by then. NW
Reporting was contributed by Julian E. Barnes, Farnaz Fassihi, Zabihullah Ghazi, Adam Goldman, Yonette Joseph, Mujib Mashal, Salman Masood, Alissa Rubin and Megan Specia.
A version of this article appears in print on Aug. 2, 2019, Section A, Page 10 of the New York edition with the headline: Death of Bin Laden’s Son Is Seen as a Blow to Al Qaeda.