Seeing the prison system for ourselves was nearly impossible; the government gave only occasional visas for tightly controlled visits. But in 2013, we got a partial glimpse. A businessman close to the Assads took me and my team to a security facility to meet prisoners he said were foreign jihadists who would prove to us that the uprising was driven not by a homegrown protest movement but by extremist Islamist terrorists.

It was my most ethically compromising moment as a journalist. A line of prisoners, hunched over and handcuffed to one another, some limping — beating the soles of the feet is a common torture method — were led through a drab courtyard and, one by one, sat across from me in an office. Behind me was a portrait of the former president of Syria, Hafez al-Assad; flanking me were the jailers.

My colleague, Hwaida Saad, and I told each prisoner that we were independent journalists, that they could tell us anything they wanted or nothing. But in reality there was no way they could safely speak freely or refuse.

The prisoners turned out to be mostly Syrians. Several gave nearly identical, implausible accounts: They had no political views, but had been approached by a religious leader out of the blue, and had been given money and drugs in exchange for engaging in random violence.

One of them did not stick to his lines. A walnut seller from a working-class suburb, he had protested, he said, “for, like, freedom.” What did that mean to him? He said he wanted to vote in a meaningful election. I worry to this day about what happened to him afterward.

We left feeling physically shaken. Our minders mocked us for “feeling sorry for them.”

We redoubled efforts to cover the story, as human rights groups steadily compiled data on dozens of torture facilities, tens of thousands of disappeared Syrians and thousands of executions of civilian oppositionists after sham trials. A defector, who went by the pseudonym Caesar, escaped with photographs of thousands of starved, bruised detainee corpses.

But in 2014, the foreign jihadists of the Islamic State seized the spotlight. They enslaved and raped minority Yazidis and executed foreign journalists on camera — actions designed and packaged for public consumption, calculated to terrify.