On 22 February 1942, Roelfzema's 'transport service' performed an infiltration for his friend Ernst de Jonge. They rowed ashore at Katwijk. Roelfzema had already become suspicious that something was amiss with their insertion operations. He feared they were being betrayed by Nazi sympathizers present amongst the officers of the exiled government. Some three months after De Jonge's drop, a courier on his way to England was picked up by the secret police. He was carrying detailed reports written by De Jonge that had been transferred onto three roles of microfilm. De Jonge heard about the arrest but refused to go into hiding. Three days later, on 22 May, De Jonge and two of his fellow agents were arrested at an apartment in Rotterdam. They were brought to Kamp Haaren. From there they were transferred to Assen. Roelfzema did not hear from him again. De Jonge and a group of 52 others were sent to the Rawicz concentration camp in Poland. Of that group, 47 were sent over to Mauthausen, where they were executed. Ernst de Jonge remained with six others at Rawicz and died there in September 1944; there is no known grave.