Rahmatullah Nabil, Afghanistan’s spy chief, at his office in Kabul, Afghanistan, Oct. 22, 2014. Many Afghans fear Nabil may be too gentle for the job. Their thinking is that defeating the Taliban, resourceful enemies who live among the Afghan people, takes a certain ruthlessness. (Lorenzo Tugnoli/The New York Times)

WASHINGTON – Unlike his predecessor, Afghanistan’s spy chief, Rahmatullah Nabil, has never been accused by human rights groups of having a torture chamber in his basement.

To the contrary, there are many Afghans who fear that Nabil may actually be too gentle for the job. Their thinking is that defeating the Taliban, resourceful enemies who live among the Afghan people, takes a certain ruthlessness.

At the same time, other Afghans and Western officials worry that Nabil is not as committed as he claims to modernizing and reining in a spy agency that grew out of a feared KGB-trained secret police force, and retains a reputation for brutality.

After stints totaling more than three years at the helm of the National Directorate of Security, and now with his nomination to keep the post in the new administration, one would presume the answers might be clearer about Nabil, 46, a former U.N. official. But he remains exceedingly difficult to pin down.

That may make him well suited to his job – the best spies are, after all, often more forgettable than dashing. And Nabil, a soft-spoken man who favors understated blazers and suits, hardly looks the part of a South Asian spymaster.

Yet with the United States and European powers sharply curtailing their role in the war, he has aggressively sought to keep the resurgent Taliban at bay, stop the remnants of al-Qaida from growing fresh roots in Afghanistan, and keep the Islamic State from winning adherents in the Afghan insurgency.

Under his leadership, the NDS has exhibited an independent streak that has surprised even the CIA, which trains, supplies and bankrolls it. Afghan spies have turned some of the region’s most notorious militants into sources and potential proxies, and the intelligence agency has clandestinely taken its fight across the border, targeting Taliban leaders sheltering in Pakistan.

In Afghanistan, these are achievements to brag about. But Nabil emphasizes none of them when talking about the NDS. He instead talks of the need to safeguard Afghans and their rights.

“Freedom of speech is part of that, respect of human rights is part of that,” he said in an interview. “We don’t want to be the political police.”

But he added a caveat: “We are in the middle of war. It is very difficult to say that we are perfect at this stage.”

The level of secrecy surrounding the agency has done little to assuage fears that it is simply a new version of the old secret police, with its own paramilitary force, high-end surveillance abilities lent by the Americans, and a mandate to monitor and detain its own people.

The agency’s record is littered with documented cases of torture and other abuses. And though Nabil has set up an internal investigative unit and given Afghan and international human rights monitors access to the agency’s facilities, human rights advocates say substantive change requires public action and prosecutions, which have yet to materialize.

The NDS, meanwhile, eavesdrops widely on Afghans. During a presidential election crisis that nearly tore apart the government last year, Afghan officials said NDS officers leaked incriminating recordings about efforts to fix the election in favor of Ashraf Ghani, the eventual winner.

Afghan and Western officials say they do not believe that Nabil played a role in leaking the tapes to the campaign of Abdullah Abdullah. Nabil was often praised by supporters of both camps for remaining relatively neutral through the crisis, and he and Ghani now meet daily.

But if factional divisions in the new government have posed a challenge for Nabil, they can hardly be more daunting than the one posed by the motley collection of former enemies that make up his own agency.

Within the modern NDS, old KGB-trained hands work alongside the mujahedeen fighters they battled in the 1980s. And both groups share a distaste for colleagues brought in when the Taliban were in power.

Nabil maintains that those internal camps all lack strategic thinking, or even a shared sense of what they should be doing. Getting them all on the same page is “our biggest challenge,” he said.

His solution has been to bring in a new generation of officials who, like himself, straddle the chasm between Afghanistan and the West.

There are former U.N. officials with computer programming degrees, and young staff members in trim suits and skinny ties who studied management at American or European universities.

Born in a rural village south of Kabul, Nabil lost his father at a young age, and spent much of his childhood with an uncle in Kabul. But he fled to Pakistan in the mid-1980s to avoid being sent to Moscow to study on behalf of Afghanistan’s Soviet-backed government.

He described life in Pakistan as hard enough that at one point his mother, who made a meager living embroidering dresses, was sending him money so he could earn a degree in civil engineering.

A postgraduation job working with refugees in eastern Afghanistan led to a position at the United Nations in Kabul. He remained there throughout the reign of the Taliban, which twice beat him for having too short a beard, he said.

It was an old U.N. colleague who brought Nabil onto the staff of President Hamid Karzai’s National Security Council in 2004, and he was soon put in charge of a new guard force being trained to protect the president.

Running what became known as the Presidential Protection Force gave Nabil a chance to prove that he was tougher than his professorial manner would suggest. His star turn came in 2008, when his men fought off an assassination attempt against Karzai during a parade as scores of police officers and soldiers at the scene scattered in disarray.

Two years later, Karzai chose him to lead the NDS after firing the agency’s director. But in 2012, he found himself on the receiving end of palace machinations when Karzai replaced him with a closer political ally.

His exile did not last long, however.

Nabil’s successor at the NDS, Assadullah Khalid, who years before had been accused of running a basement torture chamber, was severely wounded in a suicide bombing a few months into his tenure. Karzai turned again to Nabil, naming him the acting director general. This month, Ghani nominated him to the post again, pending parliamentary approval.

Among his first tasks was resuming a sensitive project he had begun during his first turn at the NDS: turning the No. 2 official in the Pakistani Taliban, Latif Mehsud, into a source – and possibly a proxy to be used against Pakistan.

Nabil said Mehsud had been cultivated primarily as a source of intelligence. But the Afghans also wanted “to send a message to Pakistan that if they can do this, we also can do it.”

No matter what it was, U.S. officials were furious about the relationship when they discovered it in September 2013. They dispatched a Special Operations team to seize Mehsud from an NDS convoy that was carrying him to Kabul last year. He is believed to remain in U.S. custody.

If Nabil is still angry about having his prize asset pried away at gunpoint, he betrayed no hint of it during the interview. And though he would not explicitly confirm that the NDS had continued to develop other militant contacts, he strongly suggested that was the case.

For his part, Nabil said the Americans “came to me, and I said that just like any other intelligence agency, we have the right to have sources.”

He added, “I think it is very important just to be very frank.”