Hartog Cohen tried to flee to Switzerland in July 1942, leaving Amsterdam with Marko (Mordechai) Gandelman, who lived at the same address, Kastanjeplein 3, where probably Hartog's mother held a boarding house. The two young men made it till the Swiss border near Pontarlier and were maybe turned back, though we have no nominal evidence of this. They were arrested in Besançon on July 21. Strangely, they were registered as «Jews suspected to prepare a (terrorist) attack». They were put into jail in Besançon (Maison d'arrêt de la Butte, German sector) and then transferred by order of the Feldkommandantur 560 to camp Pithiviers on August 8, before being sent to Drancy and later to Auschwitz on August 26 (convoy Nr. 24).
Source: Archives départementales du Doubs, 1409W40.