A U.S. Air Force F-16 Flying Falcon fighter-bomber takes off for a mission from Bagram air field in Afghanistan. REUTERS/Josh Smith

When Army Capt. Hugh Miller heard a group of policemen trading stories about a militant called Farouq al-Qahtani at their base in Afghanistan’s Konar province one day four years ago, he didn’t know what all the fuss was about. “I don’t think I even sent a report up about it,” Miller, who was deployed as a combat adviser at the time, said in a recent interview. “I didn’t know the guy was a big deal.”

Qahtani, a Saudi native with a Qatari passport whose real name was Nayef Salam Muhammad Ujaym al-Hababi, was targeted Sunday in an airstrike in Konar’s remote Helgal valley, the Pentagon announced Wednesday. Little-known outside counterterrorism circles, he was indeed a big deal: Though only in his mid-30s, Qahtani was believed to be the senior al-Qaeda operative remaining in Afghanistan at a time when many of the group’s bigwigs had decamped for Syria, and U.S. government documents suggest he may have been involved in plotting attacks abroad.

Konar and neighboring Nuristan, which blend together in the jagged 12,000-foot mountains that Qahtani has frequented for the past six years, have been the scene of some of the costliest and most publicized episodes of the whole American war in Afghanistan: Operation Red Wings, where 19 Special Operations members were killed; the many firefights in the infamous Korengal valley, where the documentary “Restrepo” was filmed; the battles of Wanat and Ganjgal, which led to both acrimonious investigations and high-profile awards for combat heroism.

In his memoir “My Share of the Task,” retired Gen. Stanley McChrystal describes how, when he took the reins of the terrorist-hunting Joint Special Operations Command in 2003, he surged hundreds of Army Rangers into Konar and Nuristan for an operation called Winter Strike. The Rangers were chasing phantoms, it turned out: The mission’s target, al-Qaeda leader Osama bin Laden, was already in Pakistan at the time.

In the years that followed, however, military reports consistently singled out the two northeastern provinces as the only part of Afghanistan with a continuous, if small, presence of al-Qaeda operatives. “Northeastern Afghanistan has become a small haven for Al Qaeda,” a leaked JSOC report from 2011 explained. “Several Al Qaeda commanders, including the Al Qaeda emir for Konar and Nuristan, Farouq al-Qahtani, now live and operate in Afghanistan, with permission from the Taliban.”

It was through JSOC’s killing of bin Laden in the Pakistani city of Abbottabad, also in 2011, that many al-Qaeda watchers first became aware of Qahtani, the up-and-comer who, to some, represented a new generation of al-Qaeda leadership — forged in the Afghan jihad just like the original crew.

Among the trove of documents that JSOC operators took from the Abbottabad compound were letters between Osama bin Laden and al-Qaeda’s operations chief at the time, Atiyah Abd al-Rahman. In one of these, Rahman wrote to bin Laden about efforts that were underway to relocate some al-Qaeda operatives from Pakistan’s tribal areas, where the CIA’s drone campaign was taking a heavy toll, to Konar and Nuristan.

“As I have reported before, we have a good battalion over there led by brother Faruq al-Qatari,” Rahman wrote. “He is the best of a good crew. He recently sent us a message telling us that he has arranged everything to receive us; he said the locations are good, there are supporters and everything.”

The gorges and ravines where Qahtani was setting up shop were good places to hide. Steep, covered in boulders and pine forests, and with very few places to land helicopters, the mountains north of Konar’s Pech valley presented every kind of natural obstacle to JSOC raid forces. In 2008, according to a trove of military incident reports released by WikiLeaks, a joint CIA-JSOC mission nearly ended in disaster in the wooded heights above the Helgal valley — where Qahtani was reportedly killed — when a Chinook helicopter with the call sign “Mastodon 34” clipped a tree and crashed into a ravine, necessitating a dangerous recovery mission.

As the conventional U.S. military closed its bases in Konar in 2012 and 2013, JSOC turned to drone strikes, launching Operation Haymaker, a scaled-down version of the CIA’s long targeted-killing campaign in Pakistan, this time focused just on Konar and Nuristan.

Haymaker and subsequent operations, which combined drones with manned surveillance and strike aircraft, killed many low- and mid-level insurgents who were thought to have links to al-Qaeda operatives like Qahtani. “Faruq al-Qahtani and Dost Mohammad and their entourages frequent Waygal,” reported a leaked Haymaker document published last year on the website, The Intercept. “Elimination of these targets will provide demonstrable measures of success.”

But Qahtani proved hard to eliminate. Not much was even known about him. No photo of him has been published, and U.S. Treasury Department information on him provides his Qatari passport number but little else. For date and place of birth, the Treasury document offers a range: Jan. 1, 1979, to Dec. 31, 1981, somewhere in Saudi Arabia.

It is a safe bet that the U.S. intelligence community knew more about him than that. In recent years, Qahtani had come to the attention of senior officials in the U.S. intelligence community, some of whom spoke and wrote about him in almost admiring terms.

“There is one particular terrorist in South Asia whom I worry the most about — Farouq al-Qahtani,” wrote Michael Morell, the former acting CIA director, in a memoir published last year. “Al-Qahtani, a Qatari by birth, is a US counterterrorism expert’s worst nightmare.” Qahtani was “smart,” “operationally sophisticated” and “a charismatic leader,” Morell continued, adding that he worried more about the young Qatari than about al-Qaeda’s overall leader, the aging Ayman al-Zawahiri.

Michael Flynn, the retired lieutenant general and former director of the Defense Intelligence Agency who now advises the Trump campaign, spoke about Qahtani in similar terms in an interview last year. “Farouq al-Qahtani is a trusted leader,” Flynn said. “When al-Qaeda goes looking for a new generation of leaders, he’s a true believer in the ideology and he will be fighting us until the day he dies.”

But what was Qahtani doing in the wild, inaccessible valleys of Konar and Nuristan? In the 2015 interview, Flynn expressed skepticism that the Qatari terrorist was using his mountainous refuge to plot attacks on the West (as an anonymous government official told NBC on Wednesday). “What he’s doing up there is not planning external operations,” Flynn said. “He’s up there planning for a role in the Taliban takeover of Afghanistan.”

Al-Qaeda operatives in Afghanistan were known to act as combat advisers, too, helping local guerrillas build bombs and plan complicated attacks. But that didn’t seem like Qahtani’s role, either. “I thought he was more like a statesman, building and maintaining relationships with the Taliban to ensure al-Qaeda access in the post-U.S.-presence era,” added a former soldier in an interview, speaking on the condition of anonymity to talk about counterterrorism operations. But that was just a guess. “What he was doing up there was open for debate.”

The Afghan government said it had confirmed Qahtani’s death. But the former soldier warned that he might not be dead. More than a few Konar-based jihadists have resurfaced after the U.S. military or Afghan government trumpeted their deaths, taking advantage of rugged cliffs, boulders and forests that make both airstrikes and aerial surveillance difficult in the region.

If Farouq al-Qahtani is indeed dead, however, his violent passing brings a sort of poetic closure to the long, costly American military experience in Konar. U.S. counterterrorism forces first went to Konar looking for senior al-Qaeda operatives. Now, more than 14  years later, they may have finally killed one there.

Wesley Morgan’s book on Afghanistan’s Pech valley is forthcoming from Random House. Follow him on Twitter: @wesleysmorgan.