He told Daily Star Online: "John Stockwell, a former CIA agent, said fellow agents were working in Afghanistan at that time and heading up the heroin trade.
"A man named Gulbuddin Hekmatyar was working for the CIA doing that.

The Nirvana frontman was found dead aged 27 after a self-inflicted gunshot wound to the head on this day 25 years ago.
His death sparked a series of conspiracy theories - with one researcher pointing the finger directly at the US government.
Author John Potash last year claimed that Cobain was among a group of musicians - including John Lennon, Jimi Hendrix, and Tupac - targeted by the CIA to prevent a leftist ideology spreading through the US.
He made the startling allegations in book Drugs as Weapons Against Us.


Now Potash has explained exactly how the CIA supposedly got the drugs to Cobain after smuggling them out of war-torn Afghanistan in the 1980s.
He told Daily Star Online: "John Stockwell, a former CIA agent, said fellow agents were working in Afghanistan at that time and heading up the heroin trade.
"A man named Gulbuddin Hekmatyar was working for the CIA doing that.
"In the late 1980s and early 1990s all this heroin was coming out of Afghanistan and coming into the US."
Warlord Hekmatyar reportedly received at least $600 million from the US for siding against the Russians in the Soviet-Afghan war.
Along with other resistance leaders, Hekmatyar increased heroin production in his region to finance his military operations.
The US secret service notoriously turned a blind eye to the opium trade - but Potash goes a step further and argues they were complicit.

He continued: "With all this supply, they needed to make it match demand.
"The way they tended to do that was to hook top musicians on drugs.
"Kurt Cobain, I argue, was psychologically profiled for this. He had his stomach problem."
Cobain suffered from intense and prolonged physical pain due to a chronic stomach condition.
He self-medicated with heroin and allegedly said he was "determined to get a habit" to alleviate the agony.

He continued: "With all this supply, they needed to make it match demand.
"The way they tended to do that was to hook top musicians on drugs.
"Kurt Cobain, I argue, was psychologically profiled for this. He had his stomach problem."
Cobain suffered from intense and prolonged physical pain due to a chronic stomach condition.
He self-medicated with heroin and allegedly said he was "determined to get a habit" to alleviate the agony.

Other experts questioned Cobain's official cause of death after seeing his toxicology report.

Canadian journalist and historian Max Wallace told 2015 documentary Soaked In Bleach: "For me, the most compelling piece of evidence that convinces me almost to a certainty that Kurt was murdered, was the level of heroin in his body.

"There has never been a documented case in the history of law enforcement where somebody could have the level of heroin in his body and still remain conscious and still lead to a suicide."