So says the Daily Mail, based on an interview with an unnamed Saudi “senior government official” with direct knowledge of the letter sent to the US. According to the official, Tamerlan Tsarnaev applied in December 2011 to enter Saudi Arabia to visit Mecca, but the Saudis got suspicious of his actual intent and denied the visa application — at which point Tamerlan went to Dagestan. The reason for the rejection wasn’t Tsarnaev’s connection to Chechnya, but because the Saudis thought he had connections in Yemen (via Drudge):

The Kingdom of Saudi Arabia sent a written warning about accused Boston Marathon bomber Tamerlan Tsarnaev to the U.S. Department of Homeland Security in 2012, long before pressure-cooker blasts killed three and injured hundreds, according to a senior Saudi government official with direct knowledge of the document. The Saudi warning, the official told MailOnline, was separate from the multiple red flags raised by Russian intelligence in 2011, and was based on human intelligence developed independently in Yemen. Citing security concerns, the Saudi government also denied an entry visa to the elder Tsarnaev brother in December 2011, when he hoped to make a pilgrimage to Mecca, the source said. Tsarnaev’s plans to visit Saudi Arabia have not been previously disclosed. The Saudis’ warning to the U.S. government was also shared with the British government. ‘It was very specific’ and warned that ‘something was going to happen in a major U.S. city,’ the Saudi official said during an extensive interview. It ‘did name Tamerlan specifically,’ he added. The ‘government-to-government’ letter, which he said was sent to the Department of Homeland Security at the highest level, did not name Boston or suggest a date for his planned attack.

If it’s true, then the FBI, DHS, and/or the CIA have a lot more explaining to do. This could be why the CIA added Tsarnaev and his mother to the TIDE system, although one would think that a Yemen connection might have prompted a higher profile in the database and a little more investigation. Since the warning came in 2012, presumably while Tamerlan was on his six-month pilgrimage to Dagestan, it should have set off all sorts of alarms when Tsarnaev returned that summer — or at least another look by the FBI, assuming they knew about the warning at all. If that was “stovepiped,” the FBI might have been unaware of it. However, if the Yemen connection was through Awlaki, that would raise questions about how much of Awlaki’s contact with the US was missed by the CIA and FBI, too.

On the other hand, let’s play skeptic for a moment. So far at least, we haven’t heard of any connection in the Tsarnaevs’ lives that would have drawn them to Yemeni jihadist groups in 2011. That doesn’t mean there weren’t opportunities — Anwar al-Awlaki was very successful in his on-line endeavors, but he had been dead for three months by December 2011. The connection to Islamist separatists and terrorists in Chechnya makes sense because of Tsarnaev’s heritage, but there isn’t anything obvious connecting the Tsarnaevs to either Saudi Arabia or Yemen.

Why would the Saudis claim to have sent the letter? Could be for PR, and it could be to further discredit Yemen, with whom they have a contentious relationship (which was one of the driving forces behind the initial radicalization of Osama bin Laden, remember). On the other hand, by claiming that they also warned the UK, it makes it more difficult to maintain a false claim — the UK has no reason to dispute that if it were true, while the US might be reluctant at this point to admit shrugging off an independent warning about Tamerlan.

On the whole, this makes for an interesting development, but it would be better to wait for some independent verification before fully embracing this single-source story.

Update: Allahpundit reminds me that an Awlaki connection had already been asserted last week:

As investigators sift through the lives of Tamerlan and Dzhokhar Tsarnaev trying to understand their radicalization and descent into violence, one clue almost seemed expected. Two U.S. officials tell The Daily Beast that, during his hospital room interrogation, Dzhokhar told FBI agents that he and his brother were influenced by the Internet sermons of Anwar al-Awlaki, the American-born preacher who was killed in a U.S. drone strike in Yemen in September 2011. The charismatic cleric was seen by the Obama administration as a uniquely dangerous terrorist because of his sermons (delivered in fluent, American-inflected English), his intuitive grasp of U.S. culture, and a burning desire to strike his birth nation.