American reporter and author Seymour Hersh has broken some of the biggest news stories of the past 50 years.

He uncovered the My Lai massacre during the Vietnam War. He revealed that U.S. soldiers were torturing and humiliating Iraqi detainees in the Abu Ghraib prison in Baghdad. And he also wrote a book about the Soviets shooting down a Korean airliner—and what the American government really knew at the time.

But his latest probe, which concluded that Barack Obama concocted a mythical story about the killing of Osama bin Laden, has been greeted with derision by the White House.

Writing in the London Review of Books, Hersh asserted in a 10,000-word article that the U.S. government collaborated with Pakistani officials.

"The most blatant lie was that Pakistan’s two most senior military leaders—General Ashfaq Parvez Kayani, chief of the army staff, and General Ahmed Shuja Pasha, director general of the ISI—were never informed of the US mission," Hersh wrote. "This remains the White House position despite an array of reports that have raised questions, including one by Carlotta Gall in the New York Times Magazine of 19 March 2014."

Hersh also claimed: "The White House story might have been written by Lewis Carroll: would bin Laden, target of a massive international manhunt, really decide that a resort town forty miles from Islamabad would be the safest place to live and command al-Qaida's operations?"

The White House's spokesperson for national security, Ned Price, issued a statement saying "the notion that the operation that killed Osama bin Laden was anything but a unilateral U.S. mission is patently false."

"As we said at the time, knowledge of this operation was confined to a very small circle of senior U.S. officials," Price said. "The president decided early on not to inform any other government, including the Pakistani government, which was not notified until after the raid had occurred."

Hersh maintained in his article that the Pakistani intelligence service, the ISI, had kept bin Laden as a prisoner in the Abbotabad compound since 2006. Moreover, Hersh reported that the army chief of staff, Gen. Ashfaq Parvez Kayami, and the director general of the ISI, Gen. Ahmed Shuja Pasha, "knew of the raid in advance".

He also claimed that the U.S. Navy Seals went into the third-floor room and simply shot bin Laden as he was living in a cell with bars on the window.

In addition, Hersh stated that Kayami and Pasha "made sure that the two helicopters delivering the [U.S. Navy] Seals to Abbotabad could cross Pakistani airspace without triggering any alarms".

When Hersh told former Pakistani ISI director Asad Durrani, about his findings, Durrani responded: "When your version comes out—if you do it—people in Pakistan will be tremendously grateful. For a long time people have stopped trusting what comes out about bin Laden from the official mouths. There will be some negative political comment and some anger, but people like to be told the truth, and what you’ve told me is essentially what I have heard from former colleagues who have been on a fact-finding mission since this episode."