It’s hard to imagine, in the sanitised, Starbucksed Manhattan of today, just what a war zone swathes of New York City were from the early 1970s to the late 1990s. First heroin then crack cocaine decimated two generations of poor New Yorkers, blacks in particular. At least some of the blame can be laid on Frank Lucas, a sharecropper’s son from North Carolina, who, in the early 1970s, became the most powerful drug lord in Harlem by selling his astonishingly pure heroin, known as Blue Magic, through an army of street dealers controlled by his brothers, the so-called Country Boys.

Lucas wasn’t the only black heroin-dealer operating in Harlem at that time, but the others had to buy their drugs at inflated prices from the Italian mafia. Lucas’s coup was to secure his own supply of heroin by flying to Thailand and doing a direct deal with the drug lords in the jungles of the Golden Triangle. What was costing his Harlem rivals $50,000 a kilo cost Lucas just $4,200. That enabled him, in true American fashion, to corner the market by selling a much better product – a purer heroin – than his competitors, at much lower prices.

“We put it out there at 4pm, when the cops changed shifts,” Lucas explained to Mark Jacobson in his 2000 magazine story The Return of Superfly. “That gave you a couple of hours before those lazy bastards got down there. My buyers, though, you could set your watch by them. By 4pm, we had enough niggers in the street to make a Tarzan movie.”

Before his heroin was put out on his turf, 116th Street, in Harlem, it was cut with “60% mannite and 40% quinine” by his “table workers”, a dozen or so young women who were “completely naked except for surgical masks”, so they couldn’t steal from him.

Lucas’s daring escapades included the so-called “cadaver connection”, bringing his drugs in from Vietnam in the false bottoms of the coffins of dead service-men. Even more astonishing, and possibly apocryphal, is what he calls his “Henry Kissinger deal”. Lucas grew desperate when he couldn’t find a plane to bring his latest shipmentof 125kg of heroin to the United States. “All we had was Kissinger,” he said. “He was on a mercy mission on account of big cyclones in Bangladesh. We knew a cook on the plane and gave $100,000 to a general to look the other way. I mean, who is gonna search f***ing Henry Kissinger’s plane?”

At one stage, Lucas was making $1m a day. He owned office buildings in Detroit, apartments in LA and a farm in North Carolina.

In 1975, Lucas was finally busted after an investigation led by Richie Roberts, a cop from Essex County, New York. In an amazing twist, Roberts, who had trained as a lawyer in his spare time, became Lucas’s defence lawyer before he came to trial. That enabled him to persuade Lucas to turn state’s evidence against Roberts’s main target, cops in the notoriously corrupt Special Investigations Unit of the New York Police Department. By 1977, 52 of the 70 officers who had worked in the unit were either in jail or under indictment, in great part because of Lucas’s evidence. His sentence was commuted to a relatively short 15 years.

Today, Roberts still works as a practising attorney. Lucas, confined to a wheelchair after breaking a leg, lives mainly on a pension. He says he has no regrets about his five-year reign as Harlem’s biggest drug lord, which left as many as 500,000 people in New York addicted to heroin. “I justify it by saying, during my time, I couldn’t get a job on Wall Street, not even washing toilets,” he now says. “I went to school three days a week, and the teacher wasn’t there two of them. I had to make a living. I didn’t want to be just a damn bum on the streets.”

American Gangster opens on Friday. Blad Runner: The Final Cut is released on December 3.

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