US authorities are investigating if the Boston Marathon bombing suspect killed in a shootout was a follower of controversial Australian Muslim cleric Sheik Feiz Mohammed.

A YouTube page with the user name Tamerlan Tsarnaev features religious videos, including one by the Sydney-born sheik titled And They Say, It's Only Sunnah, and a clip where the sheik deplores storybook boy wizard, Harry Potter, and complains that cartoons on TV "glorify nudity".

Sheik Feiz founded the Global Islamic Centre in Liverpool in 2000 and gained notoriety worldwide for his teachings, including blaming women for being rape victims.

Boston residents Tamerlan Tsarnaev, 26, and his brother Dzhokhar A. Tsarnaev, 19, were identified by the FBI in security footage walking through the crowd of spectators at Monday's Boston Marathon carrying backpacks and just hours later, a wild shootout and police chase left the older brother dead.