Johan was Bep's father. He joined Opekta in 1941 as the warehouse manager, presumably through the intercession of his daughter. Bep worked in the office and, together with the other office staff, was closely involved in caring for the people in hiding from the very beginning.
Johan and the other warehouse employees were not aware of the people in hiding. They had not been informed, in order to keep the group that was in the know small. Eventually the people in hiding decided to inform Johan as well.