Iran denies having any political prisoners, but she and human rights groups say there are actually hundreds of them. Though she can't prove Batebi's account of torture, she believes him because she knows other prisoners who have also been tortured.
Asked what the purpose of torture in Iran is, Mazahery told Cooper, "To get these prisoners to say things that the regime wants them to say. In Ahmad Batebi's case for example they wanted him to say that the blood on the shirt that he held up was not really blood … that it was you know everything from tomato sauce to blood of a sheep or what have you."
Batebi says he refused to say that or betray his fellow student activist, despite all the torture.
"They also used sleep deprivation against you, kept you up day and night. And they hung you from the ceiling with your hands tied behind your back," Cooper remarked. "At least five or six times they did this," Batebi replied.
Batebi told 60 Minutes he never knew which days he'd be tortured or which technique they would use. Once he says, they cut him, and rubbed salt in his wounds.
"I hadn't slept for maybe 72 hours. I couldn't think clearly. I was drooling. I wanted to sleep but they would slap me to keep me awake. In the final hours when even the slapping wouldn't keep me up, they cut my arms and hands and put salt in my wounds so the burning would keep me awake."
One day he says he heard his mother's voice outside his cell. He didn't know back then that it was just an audio tape. "I would hear her voice. And I would say, in this place, where there's all this torture and all this pain, they've arrested my mother also. And maybe she's in the prison cell next to me or across from me. And of course this really bothered me a lot."
"The psychological torture is extremely effective. Telling you that your mother has died or your father has passed away or playing recordings of your loved ones being tortured or even raped," Mazahery told Cooper.
Mazahery said women are tortured too.
Human rights groups don't know how much torture takes place in Iran's prisons. But three years ago, Iran's judiciary did publicly admit that torture was used to extract confessions.
Batebi told 60 Minutes that several times during his torture he wished he would die, and a few times he thought he was going to. "They made me stand on a stool. Two other people were on stools, one to my left, one to my right. And they put a rope around our necks. And they said, 'You have a death sentence and you will be executed.' And then they kicked away the other two stools. The other two people were hanging and their feet turned blue and they died. I was still on my stool. I was shaking all over."