A reader browses the latest issue of the French satirical magazine Charlie Hebdo on Jan. 15, 2015, in Frankfurt am Main, Germany. Boris Roessler/picture-alliance/dpa/AP Images

An "act of war," is how Anjem Choudary -- a radical Islamic preacher in London -- has described Charlie Hebdo's most recent cover depicting the Muslim prophet Mohammad.

Choudary voiced similar opinions in a 60 Minutes interview with Clarissa Ward in November when he condemned democracy and argued that "Islam is superior," and the media is merely "propaganda for the Western regimes."

Choudary's zealotry made him difficult to interview, Clarissa told 60 Minutes Overtime. "He's like a steamroller... and he will just keep talking at you until you literally say, 'You have to stop for a second and let me ask a question.'"

At the time of the 60 Minutes interview, Choudary had been accused of inciting Muslims across the West to join ISIS. Choudary denied those claims, but one of his young followers, Abu Rumaysah -- a convert from Hinduism -- echoed Choudary's sentiments, telling Clarissa that Sharia law should be imposed across Europe, including death by stoning.

It appears that Rumaysah took these teachings even further, and in late November he posted on Twitter that he'd "breezed through" British security and made his way into "the Islamic state," without specifically naming the country.

Choudary remains in London and continues preaching radical Islam. He was quoted in The Independent saying that Charlie Hebdo's depiction of Mohammad is sacrilegious and if the paper were to be tried in Sharia court, it would be subject to capital punishment.