But in one astonishing clip, recorded more than a year before the man, Anwar al-Awlaki, was killed by a C.I.A. drone strike in Yemen, the American-born cleric had a very different mission: to propose marriage to a third wife.
“This message is specifically for Sister Aminah,” Mr. Awlaki says in the video to his future bride, a comely 32-year-old blonde from Croatia who he hoped would join him in his fugitive existence. The woman had expressed fervent admiration for Mr. Awlaki on his Facebook page and later made clear in her own video reply that she shared his radical views, saying, “I am ready for dangerous things.”
Neither Mr. Awlaki nor his prospective wife knew it, but their match was being managed by a Danish double agent as part of an attempt to help the Danish intelligence service and the C.I.A. find the cleric’s hiding place in Yemen. The attempt failed, but the undercover agent, Morten Storm, 36, a former motorcycle gang member who had converted to Islam, continued to communicate with Mr. Awlaki. When Mr. Awlaki was killed in a drone strike on Sept. 30, 2011, Mr. Storm was certain his efforts had been instrumental in it.
But eventually Mr. Storm’s resentment at not getting what he regarded as sufficient credit boiled over. He phoned Jyllands-Posten, the second-largest newspaper in Denmark, and told the bewildered receptionist that he had helped track down one of the world’s most wanted terrorist leaders. The Danish newspaper spent 120 hours interviewing Mr. Storm and verifying his account.
Among the evidence that the burly, red-haired Mr. Storm produced to confirm his wild tale, in addition to the video of Mr. Awlaki and e-mail exchanges with him, were postcards from intelligence agents, an audiotape of a C.I.A agent he knew as Michael and a photograph of $250,000 in $100 bills — money he says the C.I.A. paid him for his role as marriage broker.
As part of that plan, the suitcase carried to Yemen by the bride, identified only as Aminah in her video messages to Mr. Awlaki, was secretly fitted with a tracking device that the C.I.A. hoped would reveal the cleric’s location, Mr. Storm told the Danish reporters. But a wary associate of Mr. Awlaki’s had her discard the suitcase when she arrived in Sana, Yemen’s capital. She traveled on to meet and marry Mr. Awlaki, but the C.I.A. plan was thwarted.
Mr. Storm’s tale shows the lengths to which American intelligence officials went to hunt down Mr. Awlaki, a leader of Al Qaeda’s affiliate in Yemen who some counterterrorism officials believed posed a greater threat to the United States than Osama bin Laden did. Their method was a variation on the traditional so-called honey trap, in which spy services use the lure of sex to ensnare male targets. Mr. Awlaki had been arrested during his years as an imam in the United States for hiring prostitutes; his two Arab wives lived apart from him in 2010, and he had asked Mr. Storm to find him a European woman willing to stay with him in hiding.
His eloquent calls for violence, scattered across the Web, helped radicalize dozens of young, English-speaking Muslims. He was added to the Obama administration’s “kill list” after intelligence officials concluded that he had helped plan the failed bombing of a Detroit-bound airliner on Dec. 25, 2009.
His influence has survived his death. A 21-year-old Bangladeshi man, charged Wednesday with trying to blow up the Federal Reserve Bank of New York in a sting operation by the F.B.I., told an undercover agent that he had formed his jihadist views listening to Mr. Awlaki’s sermons.
The killing of Mr. Awlaki, an American citizen, without a trial and based on secret intelligence, set off a legal and ethical debate in the United States. Now, in Denmark, the articles in Jyllands-Posten have prompted some Danes to ask whether their government was complicit in Mr. Awlaki’s death and, if so, whether that violated Danish law.
Mr. Storm, whose life has been threatened since he went public, is in hiding and could not be reached for comment. The Danish intelligence service said in a statement that it “cannot and will not publicly confirm whether specific individuals have been used as sources.” A spokeswoman for the C.I.A. said the agency had no comment.
In a conversation in October 2011 with Mr. Storm and a Danish intelligence officer, which Mr. Storm recorded on his cellphone and which the Danish newspaper posted online, the purported C.I.A. officer known as Michael praised Mr. Storm’s efforts and even said that President Obama had been briefed on his efforts against Mr. Awlaki.
But he said “other projects” by the agency had located Mr. Awlaki. “We were very, very close,” Michael said on the tape, comparing their position to players in a World Cup soccer championship who might have scored the winning goal but did not. Mr. Storm can be heard on the tape protesting that the C.I.A. officer was playing down his own role and Denmark’s role.
Pierre Collignon, the editor in chief of Jyllands-Posten, said in an interview that the two reporters who met with Mr. Storm over a period of months, Orla Borg and Carsten Ellegaard, corroborated much of what he said about his dealings with Mr. Awlaki, the Danish intelligence service and the C.I.A.
“We were very cautious,” Mr. Collignon said. “We were afraid he might still be a jihadist and might be luring our reporters into a trap, maybe to kidnap them. He was a criminal before becoming a devout Muslim, and it’s difficult to trust him entirely. But we were able to document his story.”
The newspaper has examined paperwork showing regular payments to Mr. Storm from the Danish intelligence service and has confirmed that the snapshot of $250,000 spilling from an attaché case — the purported C.I.A. fee — was taken at his mother’s house. Mr. Collignon said the newspaper was planning to publish more articles based on Mr. Storm’s account of his six years of undercover work if it could confirm the details.
But he said that Jyllands-Posten, which was the target of terrorist threats after it published a dozen cartoons of the Prophet Muhammad in 2005, had decided not to post another video that showed Aminah removing her head covering to prove that she had blond hair, Mr. Collignon said. He said it might be considered provocative and invade the woman’s privacy.
Aminah is hiding with Qaeda militants in Yemen and helping produce Inspire magazine, a slick English-language publication that offers bomb-making advice and taunts against the United States. She last contacted Mr. Storm a month ago, Mr. Collignon said, and told him her dream was to become a suicide bomber.