The Moorhound
Der Moorhund (original)
Two boys are helping the border guards to find a mysterious moor hound used by spies to transfer messages across the border.
Starring Günther Simon, Horst Kube, Rolf Ripperger, Dieter Perlwitz, Peter Sturm, Elfriede Florin, Wolfgang Glaser, Klaus Urban, Lotte Loebinger, Maika Joseph
It's a action & adventure and family movie, and has a rating of 7.1 out of 10 from Imdb which is usually fine for this kind of movie.
Watch it here
Not found streaming from Finland.