Tamarlan Tsarnaev (left) and Dzokhar Tsarnaev
(CBS News) -- As the Boston Marathon bombing investigation continues,
investigators are delving deeply into the lives of Tamerlan and his
younger brother Dzhokhar Tsarnaev for any clues as to what set them on a
path toward terrorism. Authorities still believe the two acted alone,
but they continue to probe potential outside influences.
lawmakers are questioning whether the suspected bombers got help. Rep.
Michael McCaul, R-Texas, said in a TV appearance on Sunday, "I think the
experts all agree that there is someone who did train these two
Up until now, authorities have said there's no evidence
suggesting the brothers were part of a larger terrorist group. Still,
House Intelligence Committee chairman, Rep. Mike Rogers, R-Mich.,
admitted the FBI wants to interview anyone who may have known about the
brother's alleged plot. Rogers said, "We still have persons of interest
that we're working to find and identify and have conversations with."
Tsarnaevs' mother may hold the key to some answers. In 2011, Russian
authorities secretly recorded a phone call between her and Tamerlan
Tsarnaev in which the two vaguely discussed "jihad." The FBI says it
only learned the details of that conversation days ago, even though
Russian authorities asked them to look into Tamerlan in 2011.
on "Face the Nation," Sen. Lindsey Graham, R-S.C., said, "The warning
letters the FBI received in March of 2011 and the CIA, I think in
November 2011, included the mother as someone to be worried about."
CBS News senior correspondent John Miller, a former assistant FBI
director, said on "CBS This Morning," "This is one of those cases where
we're looking for the radicalizer, we're looking for the bomb maker, and
as the case unfolds -- and I always say this can change -- we're coming
into our third weekend of this. But they've got a long way to go. So
far, it looks like these were the actions of Tamerlan Tsarnaev, maybe
egged on by his mother, but there doesn't seem to be a giant
organization behind it."
The suspects' mother, Zubeidat Tsarnaeva, has repeatedly
denied that she or her sons had any involvement with terrorist
As for the suggestion by some in Congress that the Tsarnaev brothers
had some sort of training, Miller said, "It suggests what members of
Congress know about bomb making. If you look at the ... instruction page
that gave them the layout for how to make the pressure cooker bomb,
they're saying the remote control aspect is something that they would
have had to go somewhere else, well, scroll down that page in the
magazine and the very next picture after the pressure cooker is how to
do the remote control. This can be done, and it can be done by dummies."
For now, both parents have put off plans to travel to the
U.S. The Tsarnaevs' father was hoping to visit his son and claim the
body of his older one, but he says he's too ill to travel. The mother
has said she is afraid if she steps foot in the U.S., she'll be
Investigators are also talking to a mystery man named "Misha."
Zubeidat Tsarnaeva says she and Tamerlan Tsarnaev turned more deeply to
the Islamic faith because of Misha's influence. Miller said of Misha,
"He's been cooperative, according to people I've spoken to. They asked
him for all the stuff they ask for in these things. 'Can we have your
computer? Can we go over your phone?' They're going to want to mirror
his hard-drive, see what his contacts were. And they see he handed
everything over, explained the relationship, said he wasn't a
radicalizer. He is a guy who is now from Rhode Island who was up in
Boston at the time, knew the family, but he doesn't emerge as a fiery
preacher or anybody of significance. So it's interesting to hear the
family version of this (person) who, to use their words, took over their
son's brain. And this guy who said, 'I gave him some perspectives on
life, but that was about it.'"
Meanwhile, the Tsarnaev's
19-year-old son and the lone surviving suspect -- Dzhokar -- remains at a
federal medical detention center 40 miles from Boston. He's locked
inside a 10-by-10-foot cell with a steel door and a slot for food.