Two weeks after the Boston Marathon bombings, the debate still rages as to whether the two men accused of orchestrating the attack acted alone, particularly among members of Congress who say they see too much evidence of planning for an isolated operation.
Authorities have said they believe only two men — Tamerlan Tsarnaev and his younger brother Dzhokhar — were involved in the attack. The younger brother has told authorities that they acted alone.
But not everyone is convinced.
"It's just too much — too much was perfectly synchronized here for this just to be two guys doing it on their own," Rep. Peter T. King, New York Republican and past chairman of the House Committee on Homeland Security, said on NBC's "Today" program Monday.
Even if only two men were involved in the bombings, as authorities have said, questions remain about whether they received outside training and all sides say the question of who or what may have radicalized or motivated the bombers is still open. That investigation stretches all the way to Russia, where the elder Tsarnaev brother spent part of last year.
In the U.S., FBI officials were seen Monday entering the home of Katherine Russell, Tamerlan's widow.
Meanwhile, the brothers' uncle accused a U.S.-based Islamist known as "Misha" of radicalizing them. But that man was identified and said he had nothing to do with the bombings.
During questioning with law enforcement authorities, the younger Tsarnaev, 19, said he and his brother acted alone and were motivated by a desire to defend Islam, in response to the U.S.-led wars in Iraq and Afghanistan. The elder Tsarnaev, 26, was killed in a shootout with police in the aftermath of the Boston Marathon bombings, which killed three and wounded more than 260.
But over the weekend, several lawmakers said the FBI is looking at more "persons of interest" in the U.S.
Rep. Michael T. McCaul, Texas Republican and chairman of the Homeland Security Committee, said the nature of the attacks, when bombs appear to have been detonated via a remote-controlled device, was more sophisticated than anything the two could have learned online.
"In my conversations with the FBI, that's the big question," Mr. McCaul said on "Fox News Sunday." "They've cast a wide net, both overseas and in the United States to find out where this person is, but I think the experts all agree that there is someone who did train these two individuals."
Lawmakers have been getting briefings from officials on the investigation, but the information hasn't produced a clear consensus.
While Mr. King suspected other actors, Sen. Claire McCaskill, Missouri Democrat, said there is no indication of a broader plot.
"There is no evidence at this point that these two were part of a larger organization; that they were, in fact, part of some kind of terrorist cell or any kind of direction," Ms. McCaskill said on CBS' "Face the Nation." "It appears at this point, based on the evidence, that it's the two of them."
Adding fuel to the fire was a report in The Wall Street Journal on Monday that DNA from a woman was found on at least one of the bombs used in the marathon attack. Officials cautioned that it is unclear whose DNA it is, and there are many explanations for how the DNA could have gotten there.
The two brothers came to the U.S. from the Caucuses, a region on the border of Europe and Asia, a decade ago. Dzhokhar became a citizen last year while Tamerlan's application had been held up, reportedly because federal authorities were seeking more information on why the FBI interviewed him in 2011.
The Associated Press reported this past weekend that Russian authorities wiretapped a phone conversation between Tamerlan and his mother, Zubeidat Tsarnaeva, in which she alluded to jihad and discussed the possibility of her elder son going to the Palestinian territories.
That would seem to contradict the mother's public statements since the Boston attack, in which she said the police were wrong about her boys' involvement.
Tamerlan Tsarnaev was placed on a government watch list before leaving for a six-month trip to Dagestan, in the Russian Caucuses, last year.
A State Department official referred a question about communications between the U.S. and Russia to the FBI. A spokesman for the FBI's Boston office declined to comment on the investigation.
White House press secretary Jay Carney said Monday that he didn't want to get into specifics about information-sharing between the U.S. and Russia but that the lines of communication are open.
"I can tell you that, obviously, the president has spoken with President [Vladimir] Putin and will continue to have conversations, of course, with his counterpart there as our governments cooperate on this matter and other issues," Mr. Carney said.
Russian forces over the weekend killed two members of a jihadist group in an early morning raid, including an associate of Abu Dujan, CNN reported; Dujan was the leader of a militant group that produced a video Tamerlan apparently linked to one of his Web pages before removing it.
Multiple news agencies have a cited a story in the Russian newspaper Novaya Gazeta, which reported that Tamerlan tried to join an insurgency in Dagestan before leaving the country in July, just days after some of the insurgents, including 23-year-old Canadian boxer William Plotnikov, were killed by Russian forces.
Evan F. Kohlmann, a New York-based terrorism consultant, said there are reasons to be skeptical of the brothers having broader ties. He said that virtually every Chechen or Dagestani jihadi organization of note has given the Boston bombings a wide berth, as have the Pakistani Taliban "and a variety of the other usual suspects in cases like this."
"I would be very, very careful about any assertions that the Tsarnaevs had outside help — especially if those assertions are not coming from the FBI," Mr. Kohlmann said in an email. "In the absence of such a claim of responsibility from any known terrorist organization — and in light of Dzhokhar Tsarnaev's apparent admission that he and his brother learned how to build bombs on the Internet — I tend to think that there would have to be a real smoking gun to serve as convincing evidence that they received outside assistance. As of now, I certainly haven't seen any such smoking gun evidence myself."
© Copyright 2015 The Washington Times, LLC. Click here for reprint permission.