Ludovic Kennedy deals in depth with the Patzig case and with WW2 alleged U-boat war crimes in a chapter Entitled 'Four Naval Atrocities' where he contrasts what happened to the two German WW1+2 U-boat Captains such as Patzig with how a British submarine war criminal, Lt Commander Antony Meirs of H.M. Submarine 'Torbay' who machine gunned helpless German/Bavarian Gebirge troops in yet ended up as Admiral President at Britain's Flensburg-Royal Maval College, Greenwich, post WW2.Meirs was also at one time British liaison officer to the U.S.Navy submarine fleet in WW2.He went on to become a Rear-Admiral so war crimes sometimes pay.
The Kennedy book -which I recommend-is called 'Truth to Tell'and was published by Black Swan books a division of Transworld Publishers, 61-63 Uxbridge Road London, England. My edition is the 1991 one.
Kennedy also explains that Patzig- the WW1 war criminal- who disappeared's two officer colleagues Dithmar and Bold tried the future Nuremburg scam of 'Befehlen sind Befehlen'-'Orders are orders' only to be told by the German Supreme court in Leipzig, in July 1921, that this was not a legitimate defence.
Both these guys though, only served a few months of their four year sentences fo their part in the criminal sinking of the 'Llandovery Castle'.
In contast WW2 U-Boat war criminal, Eck of the U-852 was shot by British firing squad in Hamburg's Altona prison post-war, as were two of his officers.