Weapons of mass destruction are the holy grail for terrorist groups, and over the years a number of organizations have announced their intentions to acquire chemical, biological, and radiological weapons. But the discovery of a laptop purportedly belonging to a member of the Islamic State is raising new questions about whether the terrorist group, which U.S. officials say is more dangerous than al Qaeda, is poised to launch a WMD attack. U.S. officials and terrorism experts said that the discovery of the laptop raises troubling questions about the Islamic State's intentions and its ability to conduct a WMD strike. But they urged caution, noting that the presence of documents on building biological weapons does not necessarily add up to an actual capability to use them. "I wouldn't dismiss the idea of a WMD attack by terrorists," said Daveed Gartenstein-Ross, a senior fellow with the Foundation for Defense of Democracies. "It's something we should guard against. But in terms of something I worry about, it's far down the list." Still, the laptop and its more than 35,000 files provide a rare and unsettling window into the Islamist State's inner workings. One U.S. official, who spoke on the condition of anonymity to discuss developing intelligence, said the files on the laptop offer some of the most precise information to date on the Islamic State's WMD aspirations. The information indicates that the Islamic State likely now has the ability to build at least some form of biological or chemical weapon, the official said.