In February 1941 Roelfzema wrote his 'Leids manifesto', which criticized German demands of excluding the Jewish students from the student societies. It called upon the students of Leiden to resist the policies of the German occupiers. At his own expense he had it printed, and during the night of 14/15 February Roelfzema and eleven of his compatriots posted it all over Leiden. Ten days later the Board of the University made a request of the students that they resist the German occupiers no further. Roelfzema wrote a reply on 6 March, pledging in principle to commit no more opposition at the university. In April he was arrested by the secret police and held for a week at the notorious "Orange hotel", a political prison run by the Germans in Scheveningen.