Umar Farouk Abdulmutallab, the 23-year-old Nigerian national charged with trying to destroy Northwest Airlines Flight 253 from Amsterdam to Detroit on December 25, was released from the hospital and removed to a federal prison as authorities try to understand how he smuggled a deadly explosive onto the plane and why, despite his family's warnings to the U.S. Embassy, he was allowed to fly. And a day after saying that "everything happened that should have," today Department of Homeland Security Secretary Janet Napolitano admitted that the system failed.

Napolitano said yesterday, "This was one individual literally of thousands that fly and thousands of flights every year," and said that air travel was "very, very safe... And he was stopped before any damage could be done... Once this incident occurred, everything happened that should have." But on the Today Show this morning, the Wall Street Journal reports that anchor Matt Lauer "pressed: How does a guy who’s on this general terror list, who buys a one-way transtlantic ticket with cash, who checks no luggage, and who’s own father has flagged him to authorities, get on the plane? Napolitano said that 'our system did not work in this instance' and no one 'is happy or satisfied with that.' She maintained 'air travel is safe.'"

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While Abdulmutallab's prominent family raised concerns about their son's radical views, American authorities only put his name on a broader watch list but not on a no-fly list—an unidentified TSA official told the NY Times, referring to years of criticism of too many people being on the watch list, “You are second-guessed one day and criticized on another"—and there was a note saying he should be questioned if he tried to reapply for a visa. An intelligence official told the Washington Post it's hard to investigate all tips, "It's got to be something that causes the information to sort of rise out of the noise level, because there is just so much out there."

Sen. Susan Collins (R-Maine) said, still, Abdulmutallab should have been inspected more thoroughly at security, "This individual should not have been missed. Clearly, there should have been a red flag next to his name." President Obama has ordered a review of airline security and tracking those with alleged terrorist ties.

Abdulmutallab had the PETN explosive sewn into his underwear, which he claims he received from Al Qaeda in Yemen. According to the NY Times, pentaerythritol tetranitrate "is in the same chemical family as nitroglycerin and among the most powerful of explosives. It was the same explosive that Richard C. Reid tried to detonate in his shoes during an American Airlines flight in December 2001. But one characteristic of PETN is that it does not easily detonate, and that apparently thwarted Mr. Abdulmutallab, officials said. Dropping it or setting it on fire will not typically detonate it." Abdulmtullab had tried to inject a liquid into it.