Abdelhakim Dekhar, the man arrested on Wednesday on suspicion of carrying out recent shootings in Paris, was convicted in 1998 for his links to a "Bonnie-and-Cyde" style murder spree in France.
He was convicted of buying a gun used in the 1994 shooting attacks by student Florence Rey and her lover Audry Maupin, in which three policemen and a taxi driver were killed.
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The annual event has earned a place in the record books ahead of the grand final of the 60th anniversary show in Austria this evening.
Local authorities said the move is necessary to "avert the growing number of deaths and increasing harm linked to psychoactive substances".
Some students argued that the centuries-old tradition of wearing gowns, suits and mortarboards to exams was 'archaic' and looked elitist.