However ill-advised it looks in hindsight, the decision of counterterrorism officials last month not to pursue a warning from the Nigerian would-be bomber's father was standard procedure for agencies flooded with unsubstantiated terrorism tips. It takes a specific threat, or an existing body of knowledge about an individual, for information to "rise out of the noise level, because there is just so much out there," an intelligence official tells the Washington Post.
After receiving the tip, US Embassy officials in Nigeria posted a "very, very thin" entry on Mutallab into TIDE, a database that gathers thousands of bits of information from around the world each day. Selected information from TIDE is downloaded daily into the FBI's Terrorist Screening Database—because the tip about Mutallab didn't make the cut, he was never considered for a watch list, in part because TIDE couldn't tell that the tip from Nigeria referred to a man who already had a valid US entry visa from a year earlier.
(More Umar Farouk Abdulmutallab stories.)