In 1992 the BBC broadcast a series of TV documentaries which show, in great detail, how the State successfully uses agent-provocateurs to incite left-wing and anarchist groups to greater levels of extremism, in order to destroy public sympathy for radical causes and to wreck activist campaigns, in this case across Europe throughout the 1960s, 1970s and 1980s. A recent Indymedia post also showed how here in the UK, the British State has been inciting radical violence to discredit protest movements since at least 1820 –

 http://www.indymedia.org.uk/en/2012/10/500844.html

As a case-in-point, and just as relevant to #Oct20, the TV documentaries show how a Fascist group called Avvanguardia Nazionale were paid by the Italian secret services to invent a fake Maoist group, who promoted themselves as more extreme than the Italian Communist Party, by fly-posting Maoist posters and taking Maoist banners and flags to ruin left-wing demos (watch from 2:09:47 into the main You Tube clip, from 32:48 into the Google video clip + still photo) -

 http://www.youtube.com/watch?v=AUvrPvV-KQo
 http://video.google.com/videoplay?docid=-5230012089196767224

Brief analysis -  http://www.youtube.com/watch?v=ORnbxbwd8KM