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Terrorist Richard Reid, who tried to blow up a jetliner with a shoe-bomb after 9/11, says he failed because that's what God wanted.

In a letter from the supermax prison in Colorado where he is serving a life sentence, Reid told a researcher he believes the bungled 2001 attempt to kill 197 passengers on American Airlines Flight 63 was permitted by Islamic law.

"I admit many people would dispute that and disagree with me on that point," the British-born Reid, 41, wrote.

"However, at the same time I also believe that it wasn’t supposed to happen, not because it was displeasing to God … rather because it was not either my time to die nor that of those on the plane with me, and he had other plans for me which include my staying in prison and other matters which I may not be aware of as of yet."

Reid's plan was foiled when a flight attendant saw him struggling to light a fuse coming from his shoe, which contained a plastic explosive. He was subdued by passengers and sedated by two doctors on board the flight from Paris to Miami.

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Dr. Kimberly Mehlman-Orozco, who is corresponding with him for a book she hopes to write, asked if he had any regrets about trying to commit mass murder. His response suggests he wishes he had planned the attack better.

“I do have some tactical regrets of a sort which I won’t go into here, but I don’t regret losing my freedom," he wrote.

In another letter to Mehlman-Orozco, Reid addressed the terrorist attacks on the Paris offices of the satirical publication Charlie Hebdo which had published a cartoon of the Prophet Mohammed.

“I do not see what happened at Charlie Hebdo as a tragedy," he said. "Rather the tragedy is that people think it is OK to demean the sacred and belittle that which is more beloved to we Muslims than their own souls."

He added, "And as the saying goes, if you play with fire you might get burned, so I have no tears for those who insult Islam.”

Mehlman-Orozco, who runs a non-profit called the Justitia Institute and has written to several convicted terrorists, said the letter shows how once terrorists are radicalized, they cling to their twisted interpretation of Islam, even after more than a decade in isolation.

"It withstands the cost versus the benefit, it withstands the will to live, it withstands years in the toughest prison in America," she said.

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