What was the criminal justice system like in Nazi Germany?

I am not a historian but, as a law student, I have studied the history of criminal law quite a bit. If you'd like me to provide sources or go into more detail please let me know before deleting the comment, as I have only German sources (studying in Switzerland) but could surely do some research if needed. In accordance with this background, my answer will exclusively revolve around legal proceedings, principles and other aspects related to the legal system as such (as opposed to "general" history). Since your question is quite specific, I will also focus on aspects related to criminal law only, not elaborating their interplay with other bodies of law such as public law or business law - although of course, all of these work together to form one single system of rules governing the daily lives of the population, and looking at only one aspect will limit the points that can be discussed here and their effects on the system as a whole. I hope that the following answer can provide some aspects that go into more depth than what a primarily historical answer could do, and please feel free to add other aspects or contact me if I made a mistake or did not abide by this sub's rules.

Systematically, I will first generally lay down how the criminal justice system under the Nazi regime worked and then address your specific question in a second (shorter) part of my answer. I’ll try to supplement my elaborations with examples because it might be a bit difficult to apply the theoretic concepts to practice for someone unfamiliar with the law, please note that those are examples that I am making up and which, therefore, do not necessarily reflect a specific case/decision made by the Nazi courts.

PART 1

After coming to power, there were a few significant things that were done either gradually or pretty much right away (which I will elaborate on below) and, in their entirety, allowed the Nazi regime to instrumentalize the criminal justice system to the point that it could no longer be considered as in accordance with the rule of law as we understand it today. Basically, the criminal justice regime implemented by the Nazis is a textbook example of how totalitarian regimes implement and strengthen their power over a population, much of which can be recognized in the systems implemented in some countries today and certainly most authoritarian regimes of the past century.

First, a large number of new criminal offenses were introduced; focusing heavily on political criticism, organization of possible resistance and "racial offenses" (such as sexual relations between Jews and non-Jews) among others. Existing criminal offenses were furhtermore either given a whole new meaning, or their scope of application was vastly increased to incorporate even the most minor actions that previously would not have been criminally relevant. For example, while the criminal norm of treason had previously only applied to the most severe acts intended to destabilize a government (such as passing on state secrets to a foreign power), it was now applicable also to much less significant acts of dissent that didn’t even relate to the government as a whole (such as getting together a small group of people to discuss criticism towards your local authorities, even if that criticism was limited to a specific act or decision of those authorities).

Second, the principle of equality before the law was fully abandoned. This means that different people had different rights, both depending on their background and the offense they had allegedly committed. In addition, special offenses tailored to only specific groups or people of the population were introduced, meaning that an act which was completely legal for some could mean the death penalty for others. Jewish people were of course among the most affected, as they had virtually lost any and all rights to a fair trial (see below) based on their religion, had a large number of often inexplicable/impossible criminal offenses to observe, and were more rigorously persecuted than those of other religions. A good example of this is the separation of society in daily aspects of their live: While non-Jews could sit on any bench in a park, Jews could be persecuted for sitting on the same bench because they were restricted to only a few benches (or not allowed to enter the park at all).

Third, the principle of non-retrospectivity was virtually rendered non-existent. Elementary to a criminal justice system under the rule of law, this principle basically states that one cannot be held accountable for committing and act that was only made a criminal offense *after* you committed it: Since it was legal to do so when you committed the act, it would go against the fundamentals of legal security to prosecute you for something that you had no reason to think was against the law (Think that tomorrow, dying your hair blue becomes illegal: if you died your hair blue *today*, you can't/shouldn't be convicted for doing so because it was *not yet* a criminal offense when you did it!). This enabled the regime to make many acts illegal that would allow them to persecute outspoken critics who, after the Nazis had come to power, were obviously much more careful - and thus would have been impossible to "eliminate", had the system continued to follow the principle of non-retrospectivity.

In combination with the previous point, this gave the regime complete power over who to prosecute for what, and even to eliminate someone they didn’t like based on completely different reasons than why the *actually* wanted them gone. For example, it was possible for them to get rid of a person who was known as being critical towards the regime without naming that criticism as the primary reason (thus preserving the face of a “just” government that wasn’t persecuting political opponents): Put very simple, if you publicly criticized the regime before they came to power, and also owned a café that previously held a reading circle where a now forbidden book had been discussed, you could be prosecuted for the latter, despite not illegal at the time, without ever mentioning your criticism of the government.

Fourth, general aspects of how to treat a criminal case before the court were ignored. Reasons that would usually need to be observed and could lead to excusing someone from punishment - such as self-defense, mental illness or heavy intoxication - were deemed inappropriate in general, or suspended for certain offenses declared to be so serious that nothing would justify them. Not only did this allow the manipulation of opponents for them to commit a crime (for example attacking them to provoke a counter-attack, for which they could later not claim their right to self-defense), it also opened doors for arbitrary decisions that did not take all circumstances into account, thus promoting the cherry-picking of aspects of the crime leading to punishment if needed, while excluding those that would make punishment seem inappropriate.

I have reached the word limit for this comment so will continue by replying to it