(CNN) -- Investigators are leaning in the direction that the same person or persons who crafted the Christmas Day underwear bomb were behind the PETN-based devices hidden in packages sent from Yemen, a U.S. government official told CNN. "The thinking is it's the same person or group of people that built the underwear bomb because of the way it's put together," said the official, who had been briefed by multiple U.S. authorities and law enforcement sources. "But this one is about four times as powerful." American authorities are now endorsing British Prime Minister David Cameron's position that the explosives were designed to take down an airplane, the official said.
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NEW: Investigators see link between devices, underwear bomb
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A female relative of the woman arrested is also being questioned
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Governments point to al Qaeda affiliate in Yemen
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The explosives were "professionally" loaded, Dubai police say
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