WASHINGTON, May 6 (UPI) -- Osama bin Laden discussed tampering with U.S. railroad tracks to derail a train on a bridge, perhaps on the Sept. 11 attacks' 10th anniversary, officials said.
A notebook from February 2010 taken from the Abbottabad, Pakistan, compound where bin Laden was killed Monday indicated bin Laden and his al-Qaida terror network considered threatening the U.S. train network on Christmas, New Year's Day and the day of the State of the Union address, the officials told The New York Times.
While there was no evidence of a specific plot, the U.S. Department of Homeland Security Thursday issued a bulletin alerting law-enforcement officials of the possibility, the Times and The Wall Street Journal reported.
An Obama administration official said documents referring to attacks on railroads were among the first to be translated from Arabic and analyzed.
Al-Qaida and other terror groups are believed to have long aspired to blow up U.S. commuter trains and subways, officials said.
The FBI in 2009 disrupted a plot to blow up trains in New York. Washington has also been a target.
The documents taken at the Abbottabad compound indicate bin Laden was in touch regularly with the terror network he created, officials told the Times.
This is contrary to what many intelligence analysts and terrorism experts had believed, the Times said.
They'd concluded bin Laden had been relegated to an inspirational figure, with little role in current and future al-Qaida operations. They based this in part on the fact that bin Laden's whereabouts and activities were shrouded in mystery in recent years, the Times said.
Officials said the CIA had bin Laden's compound under surveillance for months before Navy SEALs killed him in Monday's 1 a.m. local time assault.
The U.S. spies watched and photographed residents and visitors from a rented house nearby in what The Washington Post called "one of the most delicate human intelligence-gathering missions in recent CIA history."
The mission involved Pakistani informants and other sources to help assemble a "pattern of life" portrait of the occupants and daily activities at the bin Laden compound, the officials said.
The effort was so extensive and costly the CIA went to Congress in December to secure authority to reallocate tens of millions of dollars to fund it, U.S. officials told the Post.
The safe house played no role in the raid and has since been shut down, the Post said. This is partly out of concern for the safety of CIA assets and partly because agency considers its work finished.