Reichsführer-SS Heinrich Himmler ordered to shoot fifty "Orange" hostages after Hanns Rauter had informed him, by telephone, about Seyffardt’s death. This in spite of Seyffardt’s last wish not to take reprisals. The German occupier decided not to carry out Himmler's order. This decision was taken because they did not want the unrest among the Dutch population to increase even more. However, raids were held at various colleges and universities in Amsterdam, Delft and Wageningen. In fact, Seyffardt had been able to state that he firmly believed that the attack had been the work of students. About 600 students were arrested and transferred to camp Vught. Around 150 were deported to Germany, later on. Another consequence of the fact that especially students were considered as the perpetrators of the attacks, was that the students had to sign a “declaration of loyalty of the students” in order to study.
On February 7th, new victims were made by CS-6. “Gemachtigde voor de Volksvoorlichting” (Attorney for the national relations) Mr. H. Reydon and his wife. His wife died on the spot, Reydon himself still died six months later of his injuries, on August 24th. Henk Feldmeijer, leader of the Dutch (later on, the Germanic) SS, was out on revenge, because the resistance continued to carry out attacks on prominent NSB, collaborators and police officers. Together with Rauter, he worked out Aktion Silbertanne, also known as the “Silbertanne murders” in which Sondercommando Feldmeijer, mainly consisting of Dutch Eastern front Veterans, supported by the Sicherheitsdienst (SD) carried out liquidations of Dutch people, in retaliation for the attacks on collaborators. For every murdered Dutch national socialist or German, three Dutch, preferably intellectuals and opponents of the Nazi regime, would be shot. Silbertanne Aktion started in September 1943 and would be continued in two phases, until September 1944, killing at least 55 Dutch.
The series of attacks did not end up well for CS-6. Prior to the attack at Reydon took place, the SD already was aware of the plans of CS-6. In fact, Kastein was betrayed by a “Vertrouwensman” (agent) of the SD, Anton van der Waals. Van der Waals lent a gun to Kastein, who used it for the attack at Reydon. This was because Verleun had taken away the gun, which he used for the attack at Seyffardt, and was in hiding since then. The SD was willing to let go of Kastein in order to get to know more about the plans of CS-6 through V-man Van der Waals. However, without the knowledge of the SD, the Security Police (Sipo) arrested Kastein on February 19th. To prevent himself of betraying his resistance group, Kastein committed suicide at the Binnenhof in The Hague by jumping out of the window of the second floor, in front of the eyes of the Sipo officers. The Germans already had a large part of the resistance group on the grain and by arresting Kastein, the majority of the group would be rolled up. With the remaining group members, Verleun increased the number of attacks, but was eventually betrayed and arrested on January 7th, 1944 and subsequently shot at the Waalsdorpervlakte.