"We are aware of the video and the links to the incidents currently unfolding in Boston," Assistant Commissioner Peter Dein said. "Our Community Contact Unit regularly speaks to the sheik and we do not hold any specific concerns.

"While we continue to monitor what is happening in the US we must emphasise that there are no specific threats which cause us to alter our position."

One of Sheik Mohammed's clips on Tsarnaev's page is a five-minute attack targeting the children's fictional character Harry Potter.

The video is found inside a folder titled "islam" and had been "liked" by Tsarnaev approximately four months ago, along with another clip recorded by the sheik.

A separate folder featured two videos with Russian language titles - both have been removed.

The sheik's representatives from the Ahlus Sunnah Wal Jama'ah based at Auburn refused to respond to the matter yesterday.

A law enforcement source said Sheik Mohammed had changed his views considerably in recent years and no longer subscribed to his "radical" teachings. Both videos on Tsarnaev's page were several years old, the source said, adding that the last time police had spoken with the sheik was after the September 12 Muslim riots in Sydney last year.

"This is just baggage he's sort of stuck with - he has a different belief system now to what he had then," the source said.

"I know he wouldn't have had anything to do with any of this."