As the investigation into why and how the Boston bombers unleashed their deadly attacks continues, the focus has centered to an elusive and mysterious Muslim convert known only as Misha.

Family members of Tamerlan Tsarnaev describe Misha as the guiding influence in the elder bomber developing radicalized views – but to date it is believed that law enforcement and the media have failed to find him.

Speculation as to who Misha is wildly varies, with some suggesting he is the mastermind behind the marathon bombings while others think that he could be a Russian spy – sent to identify and keep tabs on young men like Tamerlan who are at risk of turning to militant Islam.

All that is known about him is that he is an Armenian man in his 30s with distinctive red beard and that he has disappeared – no longer living in the Cambridge, Massachusetts area.

However, family members have been telling reporters that in the years before the Boston marathon bombings, Tamerlan, 26, fell under the strong influence of a new friend, a Christian who converted to Islam and who steered the religiously apathetic young man towards adopting strong Islamic views.