NEW YORK, June 18: Al Qaeda came within 45 days of attacking the New York subway system with a lethal gas in 2003 when the plan was called off by Osama bin Laden’s deputy Ayman al-Zawahiri, according to excerpts from a book released on Time magazine’s website on Sunday.

The US officials learnt about the plot from a CIA ‘mole’ inside Al Qaeda, claimed author Ron Suskind in his book The One Percent Doctrine. The book has been excerpted in the forthcoming issue of Time magazine.

The ‘mole’ said the operatives had planned to use a small device to release hydrogen cyanide into multiple subway cars.

US officials had already discovered plans for the device on the hard drive of a computer of a Bahraini militant arrested in February 2003. They made a working model and showed it to President George Bush and Vice-President Dick Cheney, prompting order that alerts be sent through all levels of the US government.

The book says: “US intelligence got its first inkling of the plot from the contents of a laptop computer belonging to a Bahraini jihadist captured in Saudi Arabia early in 2003. It contained plans for a gas-dispersal system dubbed ‘the mubtakkar’ (Arabic for inventive). Fearing that Al Qaeda’s engineers had achieved the holy grail of terror R&D — a device to effectively distribute hydrogen-cyanide gas, which is deadly when inhaled — the CIA immediately set about building a prototype based on the captured design, which comprised two separate chambers for sodium cyanide and a stable source of hydrogen, such as hydrochloric acid. A seal between the two could be broken by a remote trigger, producing the gas for dispersal.

Ali identified the key man as Osama’s top operative on the Arabian Peninsula, Yusuf al Ayeri, a.k.a. ‘Swift Sword.’