I recently (May 2008) discovered that this childhood favorite was available as a DVD. Although I've seen a great deal of high quality movies since then (late 70's (I was 10 in 1978)), this three-episode, low budget thing still stands strong.
What's fun is that I now watched it with my 10 year old daughter, and she experiences just the same as I remember from back then: The creepy music (she had to hold my hand, even though she's been raised with watching LotR and Resident Evil), the ever changing theories of who the culprit actually is, and also complaining about the theatrical voices from an era before Norway discovered the difference between stage acting and movie acting.
This is the one and only good science fiction movie (or series) ever made in Norway. And it's still worth watching.