MANILA, Philippines – 19 year old Dzokhar Tsarnaev, one of the suspected Boston bombers, is in the hospital under armed guards, still unable to speak.

Authorities say he is facing federal charges for his alleged role in the bombing of the Boston Marathon last Monday, which killed 3 people and injured more than 170.

Dzokhar’s arrest Friday night ended a 20 hour shut-down of the greater Boston area following the killing of his elder brother, Tamerlan, in a shootout Thursday.

The brothers Tsarnaev show how the terrorist threat is evolving today.

Below is the script:

This is the face of the new terrorist. 

26 year old Tamerlan Tsarnaev is homegrown. He grew up in America, but his Chechen roots may have pulled him into the global jihad. 

It’s not the first time it’s happened.

The bombers behind Madrid in 2004 – that attack killed 191 people – and the London bombers in 2005 that killed 52 — they integrated into western society, but they harbored a deep hatred sparked by al-Qaeda’s virulent ideology.

Tamerlan and his 19 year old brother, Dzokhar, seemed like ordinary American boys.

Until you dig a little deeper.

Tamerlan’s YouTube channel shows his support of fundamentalism and violent jihad. 

This video of the black flags of Khurusan taps into al-Qaeda’s secret motivation – when an all-powerful Islamic military force will rise up and defeat the infidels. 

His playlist includes a song called “I Dedicate My Life to Jihad” and deleted links to extremist groups in Chechnya – all signs of possible online radicalization.

ROHAN GUNARATNA, AUTHOR, ‘INSIDE AL-QAEDA’: The Internet today is the principal medium of communication by terrorists and extremist groups…We have seen a number of extremist groups that are using the net to reach out to their supporters – to radicalize, to recruit people, to indoctrinate them and to get them to launch terrorist attacks.

Tamerlan may have also gotten training on the ground.

In 2011, Russia asked the FBI to interview him about suspected extremist or terrorist activity. 

In early 2012, he flew to Moscow and stayed there for at least 6 months.

The investigation continues.   

MARIA RESSA, REPORTING: The threat continues to mutate today, largely because of law enforcement triumphs since 9/11. Still, the Boston bombings showed what stayed the same – the indiscriminate killing of civilians on a symbolic day. The Internet is also another wild card, showing how easy it is to create a playlist of hate.– Rappler.com

For more details, read Boston bombings: When terrorism is a click away and From Chechnya to Boston: How the threat spreads.