The suspects behind the Woolwich beheading of a British soldier were reportedly inspired by the preachings of cleric Omar Bakri Mohammed.
According to a secret film, Bakri states that Islam's enemies are permitted to be decapitated under certain interpretations of the religion.
The radical Muslim cleric has been banned form Britain for his extremist activities and his alleged links to the Al-Qaeda, The Independent reports.
According to the report, one of the suspects, Michael Adebolajo, a British-Muslim convert of Nigerian origin, had given a video interview where he claimed that he killed Drummer Lee Rigby, 25, as he was fighting for 'Almighty Allah'.
Michael Adebowale, 22, of Greenwich is currently being considered as another suspect for the crime.
Lebanon resident Bakri Muhammed said he had seen the interview, and justified the crime by saying that he understood the feeling of rage that had motivated the attackers.
He said Islam permits such acts as he was not targeting civilians but was taking on a military man in an operation, which is considered to be a courageous and heroic act among Muslims in the Middle East.
The report also says that the two suspected killers of Drummer Rigby were already known to British intelligence outfit MI5 and, almost certainly, to counter-terrorism officers in the police, one of whom was not allowed to travel to Somalia to join the Islamist militia Al-Shabaab last year.
Muhammed is known to deliver messages on Islamic websites where he addresses Muslims to 'use the sword to remove the head of the Westeners' and said he hoped that British Muslims who are in the army in Afghanistan can be captured.
Muhammed, however, stated that he and his followers were not involved in violence while residing in the UK, as they had come to be known as the 'covenant of security' under which Islamist organisations were allowed to carry out their activities, but desisted from taking armed action in the country which had given them refuge.
Meanwhile, the Independent Police Complaints Commission has said that the shooting had been captured by a council camera and the suspects are in a hospital with non-fatal injuries.