WASHINGTON -- While in solitary confinement in an Iranian prison, Maziar Bahari, an Iranian-Canadian journalist who was imprisoned in Iran for 118 days, looked forward to his interrogation sessions. Even if he was being beaten, he explained, at least he wasn't alone.
"In the Quran they say the worst punishment for a person is to put that person in a grave," said Bahari, filmmaker and author of "Then They Came for Me." "Sometimes when you're in solitary confinement, when you're deprived of all of your senses, when you cannot see anything except for the walls around you, you think that you're in a grave."
Idaho pastor Saeed Abedini, who was released after more than three years in an Iranian prison, has yet to speak publicly about his ordeal. But what he is likely to have been through as a prisoner until his release in January can be extrapolated from the experience of other prisoners who, like Abedini, were in Iran's Evin prison.
While Evin prison is notorious for mistreatment of political prisoners, few specific details are widely known. Bahari, an Iranian-Canadian journalist arrested in Iran in June 2009 and charged with espionage, said he was warned sharply by his interrogator never to discuss with anyone what happened there.
That may be one reason Abedini has remained silent, as have most of the prisoners who were released at the same time: Washington Post reporter Jason Rezaian, former Marine Amir Hekmati, student Matthew Trevithick and businessman Nosratollah Khosravi-Roodsari.
Still, a detailed picture of life inside Evin can be put together from interviews with former prisoners like Bahari. Solitary confinement was one aspect they all had in common. All were blindfolded whenever they were taken from their cells, according to the Canadian, American and Iranian prisoners who spoke about their experiences.
Another key aspect: Each prisoner was assigned to one principal interrogator who exercised authority over virtually every aspect of a prisoner's life and served as that prisoner's only contact with the outside world.
The Washington Post reported that Rezaian was held in solitary confinement for a prolonged period. Trevithick, in an article in Time magazine, described being blindfolded outside his cell.
Roozbeh Mirebrahimi, a spokesman for a human rights monitoring group, Impact Iran, said there's no reason to think these practices weren't imposed on all prisoners at Evin. They've been in use since Human Rights Watch chronicled them in a 2008 report.
Iranian journalist Siamak Ghaderi spent more than a month in solitary confinement. Whenever he had to go to the toilet, leave his cell to go to an interrogation session -- or for any other reason -- he would be blindfolded. He was never allowed to see anything outside of the four walls of his cell.
His sentence included 60 lashes, in addition to four years in prison for "propagating against the regime," "creating public anxiety," and "spreading falsehoods" for his coverage of gay Iranians and the riots after the 2009 elections.
Ghaderi angered officials by interviewing gay Iranians after Mahmoud Ahmadinejad, the country's president at the time, asserted there were no gay people in Iran.
"They do everything to make the person confess everything," Ghaderi said. "They do physical torture, such as being blindfolded which is horrible torture for the person. Pushing the head to the toilet bowl, not allowing the person to talk to his lawyer."
The U.S. State Department, in its 2014 report on human rights in Iran, characterized the regimen used by the Tehran government as "white torture," which it defined as "a type of psychological torture that included extreme sensory deprivation and isolation."
Dr. Allen Keller, the director of a New York City Bellevue Hospital and New York University program for survivors of torture, said that the experiences recounted by the prisoners match his understanding of torture.
"Typically torture isn't just one thing; it's a lot of things happening -- solitary confinement, blindfolded, repeatedly interrogated, perhaps threatened," said Keller, an associate professor at New York University School of Medicine. "It's the sum."
Bahari said guards called his interrogator his "owner." His interrogator told him he would be present in his nightmares and that he knew all of Bahari's thoughts.
Even the day Bahari was released, his interrogator threatened to bring him back to Iran "in a bag" if he told people what happened inside the prison.
Over 16 days in Evin, journalist Dorothy Parvaz had to continually restate her life story to interrogators. She had been held in solitary confinement with no books or paper to occupy her mind. She was kept blindfolded during her daily walk outdoors.
She was summoned for interrogation at random hours, Parvaz said, giving her no time to prepare. She remained determined, though, to convince her interrogator that she was not a spy. She kept repeating that she was a journalist for Al-Jazeera.
Though disoriented, blindfolded and being yelled at, she still found it easy to remember the truth, she said of her imprisonment.
"I know this is a country that sees spying and journalism as largely the same job," Parvaz said. That makes it "impossible to win an argument."
The interrogator sometimes showed flashes of helpfulness, the prisoners said, in what seemed to be part of the tactic of forcing them to be fully dependent on them.
Occasionally, Parvaz's interrogator would take a break to peel her an orange, she recalled, or ask someone to bring her a bag of hazelnuts.
Bahari was prone to migraines, so his interrogator would bang on his head. But perversely, when Bahari complained about a headache, the interrogator would make sure he received medicine, reinforcing the dependency of the relationship.
"When you are facing one person, your experience is more personal, and it's embodied in the shape of a young, strong, fat, big man who has control over you," Bahari said.
He added that it was important to maintain a sense of identity apart from one's relationship with the interrogator. "He can beat you up whenever he wants to, he can insult you whenever he wants to," Bahari said. "That person's voice is the only voice you're hearing."
The former prisoners all recounted a difficult time adjusting to normal life after their release, including nightmares, flashbacks and other symptoms of post-traumatic stress. The prisoners released in January likely are enduring a similar adjustment period, said J. Wesley Boyd, associate professor of psychiatry at Harvard Medical School.
After traumatic events, people's stress levels "peak soon after they leave, and over time people are going to feel better," Boyd said in an interview. "It might take more to startle a person years from now than days after being released. For some people it may be their entire life."
While in prison, Bahari created his own universe inside his head with details from trips around the world, favorite songs and other memories. It was, he said, his escape.
Parvaz would sing to herself, do cartwheels, write and rewrite stories in her head that she intended to file once she was released.
Josh Fattal, an American hiker who spent 781 days in Evin and was released in 2011, would talk to himself and sing. Sometimes he would hear a knock on a wall from another prisoner. It was a "rare but amazing occurrence" whenever these moments happened, he said.
Adjusting to life after prison was a "continual battle," Fattal said.
"Every day is its own struggle," Fattal said. "There would be periods where I would feel normal for a while, where I had gotten through it and come out stronger -- and then it would come up and hit me again."