The FBI briefed the Senate yesterday and today on the progress in the Boston Marathon bombing case, but more questions than answers may have arisen from it. The Boston Globe quotes multiple sources from within the briefing that the FBI didn’t just get one warning from Russia about Tamerlan Tsarnaev, they got warned repeatedly — including after the FBI’s initial investigation of the now-deceased bomber:

Russian authorities contacted the US government with concerns about Tamerlan Tsarnaev not once but “multiple’’ times, including an alert it sent after he was first investigated by FBI agents in Boston, raising new questions about whether the FBI should have paid more attention to the suspected Boston Marathon bomber, US senators briefed on the inves­tigation said Tuesday. The FBI has previously said it interviewed Tsarnaev in early 2011 after it was initially contacted by the ­Russians. In their review, completed in summer 2011, the bureau found no ­evidence that Tsarnaev was a threat. “The FBI requested but did not receive more specific or additional information from” Russia, the agency said last week. Following a closed briefing of the Senate Intelligence Committee Tuesday, Senator Richard Burr, a North Carolina Republican, said he believed that Russia alerted the United States about Tsarnaev in “multiple contacts,” including at least once since October 2011.

This brings us back to the question of Tsarnaev’s status on watch lists. The Los Angeles Times reported yesterday that Tsarnaev’s listing had expired during his stay in Dagestan:

An FBI alert on Tamerlan Tsarnaev, one of the two brothers suspected in the Boston Marathon bombings, had expired before he returned from a visit to Russia last year, and he was not flagged for additional screening even though the FBI had interviewed him before the trip, officials said Tuesday.

The alert on Tsarnaev was more than a year old and had expired by the time he returned from six months in Dagestan in mid-2012, Homeland Security Secretary Janet Napolitanotold a senate panel Tuesday. She said she would provide more details in a classified setting. “By the time he returned, all investigations had been — the matter had been closed,” Napolitano told the Senate Judiciary Committee. The FBI interviewed Tsarnaev in 2011 after Russian authorities warned that he might have connections to Islamist militant groups. The FBI found no such evidence, however, officials have said.

Again, this seems very odd, especially given the “multiple” warnings from Russia — where one such warning was already considered unusual. The subject of these multiple warnings had traveled to the country which issued them, where he had family in the region where Islamist extremist networks are well known to operate, and at least DHS was aware of that travel. Yet the FBI allowed the listing to expire while Tsarnaev was visiting that particular region?

And here’s another good question from Michael Daly at the Daily Beast:

The FBI did not ignore the vague inquiry from the Russian government about Tamerlan Tsarnaev. Agents duly interviewed him and ran his particulars through the available databases. They seem to have been correct in determining that he did not have any connections with organized terror groups. But the very fact that the FBI had interviewed Tamerlan back in 2011 presents the possibility, however slight, that the death of another person who was buried Tuesday really might have been prevented.

That other funeral was for MIT Police Officer Sean Collier, and the question is, why the investigators who interviewed Tamerlan did not recognize him before the photos of the bombers were made public.

Agents and cops may forget a name, but they seldom forget a face. And had an investigator exclaimed, “Hey, I know that guy!” the FBI and the Boston cops could have been outside the Tsarnaev home in 15 minutes. Tamerlan and his younger brother, Dzhokhar, might have been grabbed before the public release of their pictures, before they turned so desperate that they walked up to the cruiser where Collier sat and allegedly executed him.

The fact that the Russian warning wasn’t just a “vague inquiry” but multiple alerts makes this an even more pressing question. Tsarnaev lived in Boston for years, remember, and was no tourist terrorist. Are there so many potential Tsarnaevs in Boston that no one could recall this particular face?

The Senate briefing also produced this note of caution from Sen. Saxby Chambliss. The motives may be more “complex” than has been assumed, Chambliss says. While the evidence of guilt is overwhelming, Chambliss tells CNN’s Wolf Blitzer, it may take longer to unwind the Tsarnaev brothers’ intentions for the act of terror:

“As for the ‘why’ of it, that’s going to be a very complex and comprehensive investigation,” Chambliss told CNN’s Wolf Blitzer. “I’ll be honest, it is not clear even after the interview of the suspect in custody has been conducted. It’s still not clear exactly what did this.”

Perhaps not all of the motivations are yet known or clear, but at least some of them seem to be obvious.

Addendum: At least one local mosque is refusing to hold a funeral service for him, his aunt tells NBC: