"He was sitting in a restaurant in Dallas when the Secret Service told him that President (Barack) Obama wanted to speak to him. He then learned about the assassination," documentarian Peter Schnall told.
Bush "said to us certainly there was no sense of jubilation (and) certainly no sense of happiness," Schnall stressed. "If anything, he felt that finally there was a sense of closure."
"We could see in the interview that the president was very taken by the events of that day," said Schnall, who interviewed Bush as part of a documentary on the 10th anniversary of the 9/11 attacks. "He was very emotional."
Bush, who was in a Florida classroom for an education event when he first heard about the attacks told Schnall that initially he thought a small plane had hit one of the towers at New York's World Trade Centre.
"First, I thought it was a light aircraft, and my reaction was, man, either the weather was bad or something extraordinary happened to the pilot," Bush said.
But then-White House Chief of Staff "Andy Card's Massachusetts accent was whispering in my ear-'A second plane has hit the second tower. America is under attack.'"
In light of the intense controversy surrounding the invasions of Iraq and Afghanistan, asked if he had any regrets, Bush "kind of looked at me ... and said, 'I hate that damn question,'" Schnall said.
"He did not ever use the word regret. He did not ever say he would do anything differently." But Bush did acknowledge the controversy and division created by his decisions.