In the hours before Dzhokhar Tsarnaev was charged with the crime that could lead to the death penalty, authorities tell ABC News the 19-year-old accused terrorist has started to provide his version of the events that led to the deadly Boston Marathon bomb attacks.
For all the power of the two explosions at the Boston Marathon finish line, and for all the dramatic gun fights on the streets of Watertown, and for all the suppositions about the role of disciplined, well-trained terrorists, the college student reportedly told investigators the whole attack was devised from the Internet. The two brothers, he said, had no direction or financing from governments or rogue groups overseas.
Authorities tell ABC News they now believe the two foreign-born brothers were inspired to violence by the Internet preaching's of al Qaeda leader Anwar al-Awlaki, the charismatic American-born radical jihadist, who has been dead now for more than a year. They used instructions from an al Qaeda Internet magazine to make their pressure cooker bombs. And Dzhokhar, the younger of the brothers, may not have even known about the plot until a week or so before the attack, sources told ABC News.
Seth Jones, a counter-terror expert at the RAND Corporation, said the attack's simplicity and home grown origins may wind up being some of the most chilling aspects the Boston bombing.
"This is kind of the al Qaeda modus operandi now, not relying only on operatives, but trying to get people do it yourself radicalization to build their own bombs without coming to a training camp in Pakistan or Yemen or other locations," Jones said.
"They ad-libbed part of it and made some decisions on a few elements of the bomb making but what's different about this is they took a very simple recipe and then targeted the Boston Marathon," Jones said. "And why the marathon? Because it was there, essentially, and easy. Not long in the planning."
Authorities also told ABC News it is increasingly likely that the older of the brothers, Tamerlan, devised the plot and did most of the work in pulling it together.
Tamerlan Tsarnaev, 26, died during a firefight with police early Friday morning.
"The older brother appeared to be the more radicalized of the two and was the one that drove the need to conduct the attack as well as the preparation for the attack that is building the bombs," Jones said.
As to what drove Tamerlan to violence, his younger brother has apparently told investigators it was his hatred of America, and its policies in Afghanistan and Iraq, law enforcement sources said.
Officials say they do not plan to take what the younger accused bomber has told them at face value, and that the probe will continue to examine whether there were overseas terror connections of any kind. "It would be in his interest to minimize his own role," one official said.
But the younger brother is reportedly telling investigators is consistent with what many of those who knew Tamerlan were observing -- his disgust with things American and Christian.
Authorities are continuing to uncover details of Tamerlan Tsarnaev's life in the hope their search will help provide more clarity about the motive for the deadly bombing. Federal agents spent much of Monday searching for evidence behind a Cambridge rug store, in a cluttered alley area where the Tsarnaev brothers' father used to repair cars.
The FBI sought to question Tamerlan's American wife, Katherine Russell, who was seen over the weekend leaving Tsarnaev's Cambridge apartment with her three year old daughter. A Rhode Island native, she converted to Islam and changed her name from Katharine to Karima.
Her lawyer, Amato DeLuca told ABC News that Russell was shocked by recent events.
"She couldn't believe it," DeLuca said. "Imagine, just think of yourself. You got a brother or a father or somebody and you see their picture and it's like wow, what's going on. She was in complete shock."
DeLuca also said Russell works long hours as a health care aide and suspected nothing. She was at work when she heard about his involvement four days after the bombing. DeLuca wouldn't talk about the investigation or if his client has been questioned by the FBI.
Her family issued a statement saying: "In the aftermath of the Patriots' Day horror we know that we never really knew Tamerlane Tsarnaev. Our hearts are sickened by the knowledge of the horror he has inflicted."
Evidence of troubled moments in Tsarnaev's past turned up in police records, which showed that his then-girlfriend called 911 in tears to report that he was beating her up.
And local prosecutors told ABC News that they are now exploring whether Tamerlan Tsarnaev had any connection to the brutal 2011 murder of three young men, one of whom was a friend and sparring partner.
The three were found with their throats slashed, covered in marijuana and cash.
Authorites are also looking closely at the six month trip Tsarnaev took last year to Russia and Chechnya, at a time that rebel groups there carried out a number of violent attacks. Just last year alone Dagestan lost 115 police officers in almost 300 terror attacks. A couple of years ago this street was obliterated by a car bomb. Investigators want to know whether he met with any of the notoriously fierce extremists there.
Neighbors in Cambridge told ABC News that Tsarnaev was a changed man, swearing off tobacco and alcohol, linking to extremist jihadist videos, and saying I don't have any American friends. I don't understand them. One neighbor said he expressed anger about America and Christianity.
"So with the Bible he believed that it was a cheap copy off the Koran and that it was used as an excuse for many wars fought by America to invade countries and take land away," said Elbrecht Ammon. "He mentioned how America is a colonial power and wants to take as much land as possible and most casualties are innocent people shot down by American soldiers."
On Monday, the mother of the two brothers, Zubeidat Tsarnaev, told ABC News today from Russia that Tamerlan was always the leader of her two boys, and that after the bombing he called her to say, "Everything is okay, thanks to Allah."
ABC News' Ned Berkowitz, Cindy Galli, Angela Hill, Megan Chuchmach, Rym Momtaz, Randy Kreider, and Shushannah Walshe contributed to this report.