25 April,2013 04:39 PM IST | | Agencies
Maryland Representative Dutch Ruppersberger, the top Democrat on the House Intelligence Committee, confirmed the details after a closed-door briefing with three senior national security officials on Capitol Hill.
Two Chechen-origin brothers Tamerlan Tsarnaev, 26, and Dzhokhar Tsarvaev, 19, have been accused of carrying out the deadly Boston Marathon bombings that claimed three lives and injured over 250.u00a0
Tamerlan was pronounced dead last Friday after suffering shrapnel and bullet wounds in a gunfight with police.
Dzhokhar was later arrested in connection with the bombings and is in the hospital recuperating from injuries.
Dzhokhar has been charged with conspiring to use "weapon of mass destruction" and faces death penalty.
Authorities have said Dzhokhar and Tamerlan used a pressure-cooker bomb filled with nails and ball bearings in the attack, the Politico reported.
Ruppersberger said based on information from Dzhokhar it appears the brothers learned how to build the bomb from Inspire magazine, a publication founded by Anwar al-Awlaki, the now-deceased al-Qaeda leader.
"That has always been a concern of ours," Ruppersberger said.
"That magazine was put out to recruit people for jihad." Ruppersberger also gave more details on Russia's contact with the US regarding Tamerlan.
Following Russia's request to the FBI regarding Tamerlan, Ruppersberger said US officials asked Russian authorities three times for more information, but never got a response.
At least two senators briefed on the attack one day earlier expressed concerns about insufficient sharing of information among US law enforcement agencies.
But some House lawmakers briefed yesterday disagreed, with Ruppersberger saying that the exchange of information has been "good".
"But this investigation is not complete," he added.
"Later on, these agencies will be judged.
But right now, it's way too soon to criticise or to start making political arguments or who failed or whatever.
I think we have a lot more to do and then it's fair play after the fact to evaluate, 'How did we handle this?' But it's way too soon yet," Ruppersberger said.
Ruppersberger stressed that the investigation was ongoing and officials still have many questions left to be answered about the attack.
"It's finding out who's out there, was it a third party, was it a terrorist group, who was involved, how did he get radicalised, these are all things we want to know," he said.
"Because we want to deal with that and make sure there's not someone out there who's going to do the same thing," he added.u00a0