Plan B Economics
April 20, 2013
More Evidence Authorities Had Advance Knowledge of the Boston Bombings: FBI tracked radicalised older brother 'for five years'
Russian intelligence services warned agency about Tamerlan Tsarnaev
Convinced he was in 'direct contact' with Islamist militants
May have been inspired by Chechen rebel leader man known as Russia's Bin Landen - Doku Umarov
Believed to be behind some of Russia's worst terrorist atrocities
But FBI later discounted Tamerlan as a threat
, despite telling his mother he was an 'extremist leader'