60 years Berlin Wall MfS passport control
From 1964 at the latest, MfS employees of the later passport and control units of HA VI, dressed in border troops uniforms, completely took over the control of entries and exits at the Güst (Grenzuebergangsstellen or border crossings) under Order 40/64. Not least, this was intended to prevent escape attempts, e.g., by means of passport forgery or smuggling of persons in vehicles, and to ensure compliance with the transit regulations. MfS passport control
To control the people in and out, East Germans and foreigners, was a goldmine for the Stasi. Who are these people, and where do they want to travel? Inconsistencies in a travelers document were enough to pull them out of line and have a talk with them. If someone was politically relevant, the officer reports to the relevant department for further investigation/actions. This is how millions of people find their way into Stasi’s filing system. MfS passport control
Formed in 1964 from the Passport Control and Investigation Working Group (APF); merged in 1970 with the Travel Security Working Group (ASR) and Ref. A of Department VII/Customs (Abwehr) as Department VI.
Tasks: Continuation of the tasks of the APF; also: passport and personal control in the Berlin area and at Schönefeld Airport through the deployment of passport control units (PKE); prevention of the improper use of GDR traffic routes for transit to and from West Berlin.
Watch The Stasi and the Berlin Wall | DW Documentary (German/English).
A good source on the East German border control is the German book: “Guten Tag, Passkontrolle der DDR,” only available as a second-hand book.