Determine if the sentence is true based on the text below. Choose from options.
Guido Demoor was assassinated by Joe Van Holsbeeck.

Just one week before the elections, Antwerp was the scene of the 0110 concerts, organised against racism, extremism and gratuitous violence. The event was spurred by a series of acts of "pointless violence" during the last year (the murder of Joe Van Holsbeeck, the case Hans Van Themsche and the events surrounding Guido Demoor. However, Vlaams Belang asked many musicians to boycott the event, because it "only targets Vlaams Belang". The party considered the concerts as a direct attack by the political establishment. Since 1989, the other parties have instituted a cordon sanitaire against Vlaams Belang, forcing them into the opposition, notwithstanding their increasing electorial success.
Available options: (a). yes (b). no
(b).