Washington: The Boston Marathon bombing suspects were trained in carrying out the attacks, the chairman of the House Homeland Security Committee has said.
Chairman Republican Michael McCaul also stated the FBI has launched an international investigation on the issue.
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 joined a growing number of congressional Republicans who think the brothers had outside help or influence.
He said that they were trained, considering the devices` level of sophistication and type, shrapnel-packed, pressure-cooker bombs.
The bombs were also triggered by a remote detonator like those used in remote-control toys, US officials have said.
According to the report, US officials investigating the bombings have said they so far have no evidence of a wider plot, including training, direction or funding for the attacks.
McCaul said FBI agents are going to Russia and the surrounding 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, the report added.