While the Dombrowski family were away on holiday their apartment was thoroughly searched, and further discrete enquiries were made of their neighbours and other contacts. Employees at a language school in Chemnitz reported that Dombrowski had promised them well-aid job in a decryption office near Bernau (just outside Berlin). It was also reported that he had disclosed the true nature of a college for intelligence agents to the head of an . Busch also pursued his enquiries with the wife of Alexander Karin, who came up with more testimony concerning the loose tongue of Dombrowski's wife, who was said to have shared items of supposedly secret information concerning the increasingly sophisticated "Inner German border" defences. In response, at the end of 1957 Homeland Security, having concluded that Dombrowski was unreliable, dishonest and unnecessarily talkative, set in place an operational plan to end the matter. His letters - sent and received - were subjected to intensified scrutiny and secret investigations were extended to relatives and other acquaintances in , Mahlow, and . Dombrowski's fellow concentration camp inmates were located and questioned, and his official driver was recruited as an informant. Intriguingly, the security services remained confident that their target would remain blissfully unaware of their investigations, but it is clear that by July or August 1958 at the latest, Dombrowski sensed that the Homeland Security was closing in on him.