The move has infuriated his local devotees, who told Fairfax Media that it amounts to an overreaction by over zealous authorities. However, authorities are concerned Benbrika remains a source of inspiration for a small number of radicalised young Melbourne men. Fairfax Media also understands that ASIO, federal and Victoria Police officers are investigating some associates of Ezzit and Ahmad Raad over allegations they have been recruiting Melbourne men to fight in Syria and Iraq with Islamic extremist groups. Ezzit and Ahmad Raad were jailed with Benbrika in 2009 after being arrested during Operation Pendennis over an alleged plot to bomb Melbourne landmarks in 2005. The pair, along with several other Melbourne Operation Pendennis plotters, have been released from jail having served their sentences. Federal police suspect associates of the Raads were recently involved in the alleged activities of Amin Mohamed, 23, who recently appeared before the Melbourne Magistrates' Court accused of attempting to join the war in Syria.

Police have alleged Mr Mohamed was preparing to go to Syria last September "with intent to engage ... in armed hostilities", having obtained a mobile phone number under a false name and applied for a New Zealand passport to enter Syria. He also allegedly bought a plane ticket to Istanbul and obtained contact details of Mohammad Ali Baryalei, a former Kings Cross bouncer who has been identified as the most senior Australian member of IS. The Raads are also linked to Northcote teen Adam Dahman, who last year travelled to Iraq with another member of the Raad family. In July, Dahman blew himself up in a marketplace near a Shi'ite mosque in Baghdad in a suicide attack that killed five people and was ordered by IS. Dahman's sister is married to Ahmed Raad. Another member of the Raad family, the Sydney based Zakaryah, is also believed to have died while fighting in Syria for IS. The suspected involvement of members of the 2005 Operation Pendennis terror plot in recent extremist activity in Melbourne suggests that de-radicalisation initiatives in prison have failed.

Deputy Commissioner Tim Cartwright, who declined to comment specifically on those convicted as a result of Operation Pendennis, said it could prove difficult to de-radicalise extremists. "These people will stay on the radar for a long time. "It's not likely we'll see [the terror] alert drop back in the near future, because this is a historic build-up. "We've got this build-up of people with experience, with a tendency for radicalisation." The head of Monash University Global Terrorism Research Centre, Dr Greg Barton, whose researchers are studying efforts to de-radicalise Melbourne extremists, said that "the pattern we are seeing is that people who are hardcore, don't change their beliefs, and go on to poison other people".

"There is evidence of poisonous influence by these guys [Pendennis plotters], including the Raads. "It speaks of the need to change terror legislation so we can quarantine their influence on others." Mr Barton said he supported moves to give authorities stronger powers to question and detain suspected jihadists returning from overseas conflicts. Counter-terrorism expert Neil Fergus told Fairfax Media the "only surprise" about the co-ordinated terror raids in Sydney and Brisbane on Thursday is that they did not include targets in Melbourne. Loading

"There are indications that there are at least some persons of interest in Melbourne who are not just proselytising but are actively encouraging impressionable young Australian Sunnis to join these two groups [Islamic State and Jabhat al-Nusra]," he said. With Nino Bucci, Heath Aston