The young Florida man who was arrested after posing as an Australian jihadist was a key player in a large number of online controversies, including the smear campaign against an American black activist who was publicly accused of lying about his race.

Joshua Goldberg, 20, who had been calling for terror attacks in western countries under the guise of jihadist "Australi Witness", was also at the centre of the woman-hating campaigns known as "Gamergate" and a behind a blog called "Philosophy of Rape" on which he wrote that "whores and feminazis need to be put in their place through rape".

"Fake jihadi" Joshua Goldberg had numerous online alter egos, allegedly including the Twitter handle AustraliWitness.

On online forums Reddit and 4chan, under the name European88, he uploaded thousands of anti-semitic and racist posts as a neo-Nazi, and on the specialty neo-Nazi site Daily Stormer, he his alter-ego Michael Slay did the same.

After his arrest on terrorism offences on Friday, followed by an investigation and tip-off to police by Fairfax Media, Daily Stormer disavowed him, with site administrator Andrew Anglin writing: "Wacko Jew Terrorist Joshua Goldberg Attempted to Infiltrate the Daily Stormer".