A new book by Ron Suskind states that an Al-Qaeda cell plotted the attack but was called off by Bin Laden's No. 2 only 45 days from zero hour, according to a new book by Ron Suskind

Al-Qaeda terrorists came within 45 days of attacking the New York subway system with a lethal gas similar to that used in Nazi death camps. They were stopped not by any intelligence breakthrough, but by an order from Osama bin Laden's deputy, Ayman Zawahiri. And the U.S. learned of the plot from a CIA mole inside al-Qaeda. These are some of the more startling revelations by Pulitzer Prize-winning author Ron Suskind, whose new book The One Percent Doctrine is excerpted in the forthcoming issue of TIME. It will appear on Time.com early Sunday morning.

U.S. 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. The prototype confirmed their worst fears: "In the world of terrorist weaponry," writes Suskind, "this was the equivalent of splitting the atom. Obtain a few widely available chemicals, and you could construct it with a trip to Home Depot – and then kill everyone in the store."

Read the full story in Time Magazine.