Tamerlan était en contact direct avec les islamistes tchétchènes au Daghestan, le FBI le savait.

- Tamerlan a effectué un voyage de six mois au Daghestan l'année dernière.

- Les services de renseignements russes avaient prévenu les Etats-Unis de la dangerosité de Tamerlan.

- Depuis cinq ans le FBI surveillait les agissements de Tamerlan, souvent connecté aux islamistes tchétchène via Internet quand il n'était pas sur zone.

C'est ce que nous apprend l'article du Daily Mail du 21 avril (extrait)

"One of the brothers suspected of the Boston Marathon bombings had direct contact with Chechen terrorists – and was ‘monitored’ by investigators for five years.One of the brothers suspected of the Boston Marathon bombings had direct contact with Chechen terrorists – and was ‘monitored’ by investigators for five years. 

The Mail on Sunday has learned that the FBI put Tamerlan Tsarnaev, 26, under surveillance after receiving an explicit warning from the Russian intelligence services.

But despite apparently telling his mother that Tamerlan was an ‘extremist’ leader, the FBI eventually discounted the possibility that he was a threat....

US congressmen have expressed concern that the tip-off about Tamerlan to the FBI from Moscow may not have been properly followed through. (...)

According to an intelligence source, Russia remained convinced that Tamerlan, an ethnic Chechen, was in ‘direct contact’ with Islamist militants, most likely based in the strife-torn southern Russian region of Dagestan, where he lived for two years with his family prior to moving to the US.

During a six-month visit to Russia last year – a trip US investigators are investigating –  it is understood Tamerlan visited Dagestan, which is now regarded as more unstable than Chechnya.

One theory is that Tamerlan and Dzhokhar, who was in thrall to his older brother, may have been ‘inspired’ by a rebel leader known as Russia’s Bin Laden.

Doku Umarov, like the Tsarnaev brothers, is an ethnic Chechen from the war-torn Caucasus region that lies between Europe and Central Asia. He has been accused of masterminding some of the worst terrorist atrocities in Russia, including suicide bombings carried out by two women on Moscow’s Metro system in 2010 which killed at least 40."

Significantly, while Umarov was originally fighting only for Chechen independence he has more recently embraced a wider jihadist agenda."