Warning over post-Taliban regime In an exclusive interview with The Telegraph, he reveals for the first time the full horror of what has been happening in the name of religion in Afghanistan. Mr Hassani has the pinched face and restless hands of a man whose night hours are as haunted as any of his victims. Now aged 30, he does not, however, fit the militant Islamic stereotype usually associated with the Taliban.
Married with a wife and one-year-old daughter, he holds a degree in business studies, having been educated in Pakistan, where he grew up as a refugee while his father and elder brothers fought in the jihad against the Russians. His family was well off, owning land and property in Kandahar to which they returned after the war.
"Like many people, I did not become a Talib by choice," he explained. "In early 1998 I was working as an accountant here in Quetta when I heard that my grandfather - who was 85 - had been arrested by the Taliban in Kandahar and was being badly beaten. They would only release him if he provided a member of his family as a conscript, so I had to go."
Mr Hassani at first was impressed by the Taliban. "It had been a crazy situation after the Russians left, the country was divided by warring groups all fighting each other. In Kandahar warlords were selling everything, kidnapping young girls and boys, robbing people, and the Taliban seemed like good people who brought law and order."
So he became a Taliban "volunteer", assigned to the secret police. Many of his friends also joined up as land owners in Kandahar were threatened that they must either ally themselves with the Taliban or lose their property. Others were bribed to join with money given to the Taliban by drug smugglers, as Afghanistan became the world's largest producer of heroin.
At first, Mr Hassani's job was to patrol the streets at night looking for thieves and signs of subversion. However, as the Taliban leadership began issuing more and more extreme edicts, his duties changed.
Instead of just searching for criminals, the night patrols were instructed to seek out people watching videos, playing cards or, bizarrely, keeping caged birds. Men without long enough beards were to be arrested, as was any woman who dared venture outside her house. Even owning a kite became a criminal offence.
The state of terror spread by the Taliban was so pervasive that it began to seem as if the whole country was spying on each other. "As we drove around at night with our guns, local people would come to us and say there's someone watching a video in this house or some men playing cards in that house," he said.
"Basically any form of pleasure was outlawed," Mr Hassani said, "and if we found people doing any of these things we would beat them with staves soaked in water - like a knife cutting through meat - until the room ran with their blood or their spines snapped. Then we would leave them with no food or water in rooms filled with insects until they died.
"We always tried to do different things: we would put some of them standing on their heads to sleep, hang others upside down with their legs tied together. We would stretch the arms out of others and nail them to posts like crucifixions.
"Sometimes we would throw bread to them to make them crawl. Then I would write the report to our commanding officer so he could see how innovative we had been."
Here, sitting in the stillness of an orchard in Quetta sipping tea as the sun goes down, he finds it hard to explain how he could have done such things. "We Afghans have grown too used to violence," is all he can offer. "We have lost 1.5 million people. All of us have brothers and fathers up there."
After Kandahar, he was put in charge of secret police cells in the towns of Ghazni and then Herat, a beautiful Persian city in western Afghanistan that had suffered greatly during the Soviet occupation and had been one of the last places to fall to the Taliban.
Herat had always been a relatively liberal place where women would dance at weddings and many girls went to school - but the Taliban were determined to put an end to all that. Mr Hassani and his men were told to be particularly cruel to Heratis.
It was his experience of that cruelty that made Mr Hassani determined to let the world know what was happening in Afghanistan. "Maybe the worst thing I saw," he said, "was a man beaten so much, such a pulp of skin and blood, that it was impossible to tell whether he had clothes on or not. Every time he fell unconscious, we rubbed salt into his wounds to make him scream.
"Nowhere else in the world has such barbarity and cruelty as in Afghanistan. At that time I swore an oath that I will devote myself to the Afghan people and telling the world what is happening."
Before he could escape, however, because he comes from the same tribe, he spent time as a bodyguard for Mullah Omar, the reclusive spiritual leader of the Taliban.
"He's medium height, slightly fat, with an artificial green eye which doesn't move, and he would sit on a bed issuing instructions and giving people dollars from a tin trunk," said Mr Hassani. "He doesn't say much, which is just as well as he's a very stupid man. He knows only how to write his name `Omar' and sign it.
"It is the first time in Afghanistan's history that the lower classes are governing and by force. There are no educated people in this administration - they are all totally backward and illiterate.
"They have no idea of the history of the country and although they call themselves mullahs they have no idea of Islam. Nowhere does it say men must have beards or women cannot be educated; in fact, the Koran says people must seek education."
He became convinced that the Taliban were not really in control. "We laughed when we heard the Americans asking Mullah Omar to hand over Osama bin Laden," he said. "The Americans are crazy. It is Osama bin Laden who can hand over Mullah Omar - not the other way round."
While stationed in Kandahar, he often saw bin Laden in a convoy of Toyota Land Cruisers all with darkened windows and festooned with radio antennae. "They would whizz through the town, seven or eight cars at a time. His guards were all Arabs and very tall people, or Sudanese with curly hair."
He was also on guard once when bin Laden joined Mullah Omar for a bird shoot on his estate. "They seemed to get on well," he said. "They would go fishing together, too - with hand grenades."
The Arabs, according to Mr Hassani, have taken de facto control of his country. "All the important places of Kandahar are now under Arab control - the airport, the military courts, the tank command."
Twice he attended Taliban training camps and on both occasions they were run by Arabs as well as Pakistanis. "The first one I went to lasted 10 days in the Yellow Desert in Helmand province, a place where the Saudi princes used to hunt, so it has its own airport.
It was incredibly well guarded and there were many Pakistanis there, both students from religious schools and military instructors. The Taliban is full of Pakistanis."
He was told that if he died while fighting under the white flag of the Taliban, he and his family would go to paradise. The soldiers were given blank marriage certificates signed by a mullah and were encouraged to "take wives" during battle, basically a licence to rape.
When Mr Hassani was sent to the front line in Bagram, north of Kabul, a few months ago, he saw a chance to escape. "Our line was attacked by the Northern Alliance and they almost defeated us. Many of my friends were killed and we didn't know who was fighting who; there was killing from behind and in front. Our commanders fled in cars leaving us behind.
"We left, running all night but then came to a line of Arabs who arrested us and took us back to the front line. One night last month I was on watch and saw a truck full of sheep and goats, so I jumped in and escaped.
"I got back to Kandahar but Taliban spies saw me and I was arrested and interrogated. Luckily I have relatives who are high ranking Taliban members so they helped me get out and eventually I escaped to Quetta to my wife and daughter.
"I think many in the Taliban would like to escape. The country is starving and joining is the only way to get food and keep your land. Otherwise there is a lot of hatred. I hate both what it does and what it turned me into."