There was no evidence that the plot ever advanced beyond the conceptual stage, the officials stressed.
Other gleanings from the roughly 100 pieces of computer gear seized Sunday included possible leads on the whereabouts of other senior al-Qaeda leaders. While intelligence officials declined to comment on specific tips, a key congressional leader briefed on the findings suggested that the search for al-Qaeda’s No. 2 leader was in a newly active phase.
“We have lots of information on him,” said Rep. Mike Rogers (R-Mich.), chairman of the House intelligence committee. “I can’t say it’s imminent, but I do believe we’re hot on the trail.”
Rogers predicted that the intelligence leads from the bin Laden raid are “going to be a good for the global war on terrorism in the months ahead.”
The CIA and other intelligence agencies have been working intently since Sunday to download files and images from the computers, hard drives, flash drives and DVDs found in bin Laden’s hideout in the northeastern Pakistani city of Abbottabad. Navy SEALs who shot and killed the al-Qaeda leader hauled away boxes of such material after the raid, and also found phone numbers and cash sewed into bin Laden’s clothing.
The task of identifying and exploiting intelligence tips has been assigned extraordinary urgency, since the raid likely alerted top al-Qaeda figures that their safe houses and plans may have been compromised, said a U.S. official familiar with the CIA’s scouring of the bin Laden trove.
“Other leaders of al-Qaeda should be concerned,” said the official, who agreed to discuss the ongoing operation on the condition of anonymity. “The U.S. government is on to many of them.”
U.S. officials confirmed that the seized computers and files did contain references to plots, though in many cases the documents described plans that appeared to be only aspirational. Until this week it was not publicly known that al-Qaeda had recently contemplated a railway attack on the Sept. 11 anniversary, though the intelligence community has long known of al-Qaeda ambitions to launch terrorist attacks on U.S. rail and subway stations.
As a precaution, the Department of Homeland Security sent out an alert Thursday advising federal, state and local agencies about the new evidence of a possible rail plot.
“As of February 2010, al-Qaeda was allegedly contemplating conducting an operation against trains at an unspecified location in the United States on the 10th anniversary of September 11, 2001,” said department said in its advisory. “As one option, al-Qaeda was looking into trying to tip a train by tampering with the rails so that the train would fall off the track at either a valley or a bridge.”
DHS press secretary Matt Chandler said there was no evidence that the plans had been updated since February 2010, and the plot information was based on “initial reporting which is often misleading or inaccurate.”
“We have no information of any imminent terrorist threat to the U.S. rail sector,” Chandler said.
As a precaution, the department has ordered or encouraged additional security measures as a precaution, including the deployment of additional security officers at airports and other transportation facilities, he said.
Staff researcher Julie Tate contributed to this report.