how great that You are searching for this topic too. My grandfahter was arrested too in Kornwestheim (after being a usual prisoner of war - POW).
The Allied arrested many people in these Civil internment camps (CIC) to garantee a secure and Nazi guerilla free Post war Germany. Himmler tried to establish a so called Werwolf movement as a Nazi guerilla organisation which never really worked after german capitulation.
The Arrestment in these camps was performed following defined Arrestment categories. Beside people suspicious of being war criminals the most of the interned people belonged to organizations defined by the Nurembug tribunal as criminal organizations like SS, Waffen-SS, Gestapo and SD. The higher ranks of NSDAP party members were arrested too in so called automatic arrest (AA) in these camps.
My gradfather was automatically arrested too, because he mentioned that he was a SS member for four years before war.
He was imprisoned for three years without any personal detention order, any impeachment and without trial. In 1946 he was transferred from Kornwestheim (CIC No. 75) to Civil internment camp No. 91 in Darmstadt, where he stayed til 1948. After he was released in 1948 he got his personal denazification trial in the so called Spruchkammern („speakig chambers“ - special tribunals for denazification).
It can be true, that Your gradfather really had bad luck to be arrested, because many war criminals and mass murderers (for example members of german Police Bataillons) were not arrested, because they didn't belong to the allied arrest categories.
You can probably still find Your grandfather's documents (his so called Spruchkammer-Akten) in a german archive today. I found my own grandfathers documents in the archive of Hessen in Wiesbaden. Where Your grandfather's Spruchkammerakten are, depends on the first place of his living directly after the internment.
If You have no informations about that, You can ask in the first place the archive of the Kornwestheim documents:
Frau Gabriele Benning
Arsenalplatz 3 - 71638 Ludwigsburg
Tel: 07141/18-6320 - Fax: 07141/18-6311
If You need translation for this purpose, I can help You.
Actually I'm very glad, to find someone, who is searching for some light in this dark theme too!
I hope You are still interested in the topic and I'm looking forward to hear from You.
With the very best regards
In german language You can find some books about Civil internment camps (CIC) and denazification:
Heiner Wember: Umerziehung Im Lager: Internierung und Bestrafung von Nationalsozialisten in der Britischen Besatzungszone Deutschlands. Dissertation, Klartext Verlag. Essen. 1. Auflage, 1991; 2. Auflage 1992, 3. Auflage 2007
This book is about the British internment camps.
Wilma Ruth Albrecht: Entnazifizierung: Der verfehlte politische Neubeginn in Westdeutschland. 2007
A very vivid description of the Kornwestheim conditions You can find in Heinrich Zerkaulen's „Zwischen Nacht und Tag“. The novellist Zerkaulen wrote very successful books in Nazi Germany. He was imprisoned in Kornwestheim for some months too.