I don't have a single American friend. I don't understand them: Boston suspect once wrote

The Boston marathon bomber (white hat) who is still on the loose and is being sought by police has been identified by AP sources as 19-year-old Dzhokhar Tsarnaev, a resident of Cambridge, Massachusetts.

The second suspect (black hat), who is now dead, is said to be his brother. The older brother suspected to be Tamerlan Tsarnaev went to Bunker Hill Community College. He wanted to become an engineer.

As per CNN, Tamerlan a boxer, posted a message on his Facebook page: I don't have a single American friend. I don't understand them.

Here is a photo feature on Tamerlan, the boxer by photographer Johannes Hirn http://johanneshirn.photoshelter.com/gallery/-/G0000VQW7v6xWA7o/

Some questions investigators are asking:

How taught the brothers how to make explosives?
What motivated them?
Who detonated the explosives on the first suspect's body?

The Massachusetts governor Deval Patrick says: This is a rapidly developing situation. Everyone in Boston must stay indoors.