More top Republicans: Bomb plot perhaps involved others, FBI to investigate worldwide

The chairman of the House Homeland Security Committee said Sunday he thinks the Boston Marathon bombing suspects were trained in carrying out the attacks and stated the FBI has launched an international investigation on the issue.

Chairman Rep. Michael McCaul told “Fox News Sunday” that suspects Dzhokhar and Tamerlan Tsarnaev perhaps had help and that their mother played a "very strong role" in their radicalization process.

The Texas Republican joins a growing number of congressional Republicans who think the ethnic Chechen brothers had outside help or influence.

He thinks they were trained, considering the devices' level of sophistication and type -- shrapnel-packed, pressure-cooker bombs.

Homemade bombs built from pressure cookers have been a frequent weapon of militants in Afghanistan, India and Pakistan. And Al Qaeda's branch in Yemen once published an online manual on how to make one.

In addition, the bombs were triggered by a remote detonator like those used in remote-control toys, U.S. officials have said.

“That leads me to believe there was a trainer,” McCaul said.  "Are they overseas in the Chechen region or are they in the United States? In my conversations with the FBI, that's the big question.”

He also said agents have cast a wide net overseas and in United States, “but I think the experts all agree that there is someone who did train these two individuals."

The Tsarnaevs purportedly dropped, then detonated two bombs near the finish line of the April 15 race, killing three and injuring more than 260 others.

A criminal complaint outlining federal charges against Dzhokhar Tsarnaev described him as holding a cell phone in his hand minutes before the first explosion.

U.S. officials investigating the bombings say they so far have no evidence of a wider plot, including training, direction or funding for the attacks.

However, McCaul thinks the Obama administration has hastily said the brothers acted alone.

“They just got captured,” he said. “Yet the narrative being played out by the administration is there is no connection. … It’s a rush to judgment.”

McCaul said FBI agents are going to Russia and the surround region and just got a hold of a computer used by at least one of the suspects, who emigrated from southern Russia to the Boston area over the past 11 years.

“It’s the right of the American people to see where the investigation goes,” he said.

The 26-year-old Tamerlan was killed several days after the terror attack in a shootout with police. The 19-year-old Dzhokhar was captured in the manhunt and is now at a medical detention center.

California Democratic Rep. Adam Schiff, also a member of the House Intelligence Committee, said Sunday that the suspects being linked to a major terror group appears unlikely.

However, he told CNN’s “State of the Union: "It does look like a lot of radicalization was self-radicalization online, but we don't know the full answers yet."

House Intelligence Committee Rep. Mike Rogers, R-Mich., also said Sunday the brothers appeared to have had help in getting the bombs together.

"Absolutely, and not only that, but in the self-radicalization process, you still need outside affirmation," he told ABC’s “This Week.” "We still have persons of interest that we're working to find.”

On Friday, Utah Republican Rep. Jason Chaffetz said he was not convinced the brothers acted alone.

"I don't think it's necessarily just two kids who watched some YouTube videos and went awry and decided to do this mayhem," Chaffetz, a member of the House Homeland Security Committee, told CSPAN.

However, Missouri Democratic Sen. Claire McCaskill said Sunday there is no evidence so far that the brothers were part of a larger organization or terror cell.

"It appears, at this point, based on the evidence, that it's the two of them," McCaskill, a member of the Senate Homeland Security and Governmental Affairs Committee, told CBS' "Face the Nation."

In recent years, two would-be U.S. attackers reported receiving bomb-making training from foreign groups but failed to set off the explosives.

A Nigerian man was given a mandatory life sentence for trying to blow up a packed jetliner on Christmas Day 2009 with a bomb sewn into his underwear. Umar Farouk Abdulmutallab had tried to set off the bomb minutes before the Amsterdam-to-Detroit flight landed.

The device didn't work as planned, but it still produced smoke, flame and panic. He told authorities that he trained in Yemen under the eye of Anwar al-Awlaki, a radical American-born cleric and one of the best-known Al Qaeda figures.

A U.S. drone strike in Yemen killed al-Awlaki in 2011.

In 2010, a Pakistani immigrant who tried to detonate a car bomb in New York's Times Square also received a life sentence. Faisal Shazad said the Pakistan Taliban provided him with more than $15,000 and five days of explosives training.

The bomb was made of fireworks fertilizer, propane tanks and gasoline canisters. Explosives experts said the fertilizer wasn't the right grade and the fireworks weren't powerful enough to set off the intended chain reaction.

The Associated Press contributed to this report.