He gave 25 August 1939 as the invasion date, but this date passed by. At 14:50 on that day Hitler gave the order for the invasion, but revoked it when he heard that England was not going to concede. Sas' credibility suffered. When he reported on 31 August that the war was now close, the head of intelligence, Van der Plassche did not believe him. Sas was the only one who delivered this report: London and Paris gave reassurance. However the Netherlands mobilised at the insistence of Queen Wilhelmina. General Reijnders, still his superior in The Hague, was positive over Sas' information. His relationship with General Reijnders remained good as long as the neutrality of Netherlands was not discussed. During September and October 1939, Sas obtained more signals that the neutrality of the Netherlands would not remain inviolate. Oster, during this time, assured him that only Belgium would be the target. However Sas did not believe this. At his insistence, Oster obtained further information from the German headquarters in Zossen. This showed that the suspicions that Sas now had were correct: the Netherlands would be invaded together with Belgium. The violation of neutrality would not be limited to a passage through southern Limburg into Belgium. Sas died in the 1948 KLM Constellation air disaster in Scotland.