The CIA supported various Afghan rebel commanders, such as Mujahideen leader Gulbuddin Hekmatyar, who were fighting against the government of Afghanistan and the forces of the Soviet Union which were its supporters. More on this topic: https://www.amazon.com/gp/search?ie=UTF8&tag=tra0c7-20&linkCode=ur2&linkId=a43d44e99049527d1f34a7ebad553c65&camp=1789&creative=9325&index=books&keywords=cia%20drugs
Historian Alfred W. McCoy stated that:
"In most cases, the CIA's role involved various forms of complicity, tolerance or studied ignorance about the trade, not any direct culpability in the actual trafficking ... [t]he CIA did not handle heroin, but it did provide its drug lord allies with transport, arms, and political protection. In sum, the CIA's role in the Southeast Asian heroin trade involved indirect complicity rather than direct culpability."
In order to provide covert funds for the Kuomintang (KMT) forces loyal to General Chiang Kai-shek, who were fighting the Chinese communists under Mao Zedong, the CIA helped the KMT smuggle opium from China and Burma to Bangkok, Thailand, by providing airplanes owned by one of their front businesses, Air America.
Released on April 13, 1989, the Kerry Committee report concluded that members of the U.S. State Department "who provided support for the Contras were involved in drug trafficking... and elements of the Contras themselves knowingly received financial and material assistance from drug traffickers."
In 1996 Gary Webb wrote a series of articles published in the San Jose Mercury News, which investigated Nicaraguans linked to the CIA-backed Contras who had smuggled cocaine into the U.S. which was then distributed as crack cocaine into Los Angeles and funneled profits to the Contras. The CIA was aware of the cocaine transactions and the large shipments of drugs into the U.S. by the Contra personnel and directly aided drug dealers to raise money for the Contras. Although he heavily implied CIA involvement, Webb never claimed to have made a direct link between the CIA and the Contras. Moreover, Webb's articles were heavily attacked by many media outlets who questions the validity of his claims, although the unusual response led some to question if the CIA was involved. Webb turned the articles into a book called, Dark Alliance: The CIA, the Contras, and the Crack Cocaine Explosion." On December 10, 2004, Webb committed suicide, dying of two gunshot wounds to the head.
In 1996, CIA Director John M. Deutch went to Los Angeles to attempt to refute the allegations raised by the Webb articles, and was famously confronted by former Los Angeles Police Department officer Michael Ruppert, who testified that he had witnessed it occurring.
The CIA has been accused of moneylaundering the iran-contra drug funds via the BCCI, the former U.S. Commissioner of Customs William von Raab said that when customs agents raided the bank in 1988, they found numerous CIA accounts. The CIA also worked with BCCI in arming and financing the Afghan mujahideen during the Afghan War against the Soviet Union, using BCCI to launder proceeds from trafficking heroin grown in the Pakistan-Afghanistan borderlands, boosting the flow of narcotics to European and U.S. markets.