What changes happened in law enforcement and criminal trials during the Nazi era in Germany?

Like all totalitarian societies, the "Third Reich" had an expansive and efficient police capability. There were no "rights" in the sense of the Bill of Rights like the United States has. Individual police captains and magistrates had wide ranging powers to decide on criminal matters. Police could lock up private citizens for any reason for any length of time. It was mostly a system based on delegated power, not on procedures of justice. This system relied completely on the honesty and fairness of individual bureaucrats rather than on process.

For example, let's say your friend got arrested for theft, just on suspicion, no proof. A magistrate still might send him to jail, just because the police said they suspected he was a thief. But now, let's say you think the policeman involved had a personal reason for arresting your friend and trumped up the charges. In that case you could complain to some higher official who would investigate. If your complaint turned out to be true, the policeman would get in SERIOUS trouble (like get-sent-to-a-camp trouble). That's the way the system worked. The officials had total power, but if they were caught abusing the power, the system would turn against them hard, very hard.

This system resulted in a very safe, crime-free but fearful environment. Everyone was always very fearful, because you needed to avoid even the suspicion arising that you might have done something wrong. Even the officials were afraid all of the time, because a higher official had the same power over them, that they had over citizens.

As the economy collapsed, the system became very vicious because "economic crimes" like black market trading were necessary to feed yourself or get other necessities. This turned everyone into "criminals", so life became one of everyone living in total fear all the time of being punished.

The most important change is that after the enabling acts there were two systems of law. The SS detained whomever it pleased in Concentration Camps (although most hardly even qualify as a camp, see KZ for descriptions of how the remaining opposition was quashed.) So although the regular police were eventually integrated into the SS by way of the SD they weren't really police in the sense of upholding a uniform set of law.

Although it is fiction I highly recommend the Berlin Noir books by Kerr. The series is based upon a detective who leaves the Berlin police because of the conditions...

The laws against "normal" crimes remained in tact, it was only AFTER criminals were detained that the difference became clear: ordinary criminals were appointed as Kapo's (it is not really clear where the word originated - the Italian capo for boss would be the most likely), who were allowed to perform a reign of terror over the political prisoners and Jews.

The Nazis actually ramped up law enforcement through use of paramilitary and broadening of police jurisdiction, allowing "preventative action" arrests, and other actions that ended up causing a drop in crime. Crimes were treated the same as in the Weimar Republic, but of course there was a lot more racist and totalitarian undertone.

Source

1. Criminals were sent to concetration camps (like the non-criminals by most of a modern democracy's standards) in which the treatment was not in accordance with common standards, such as non-torture. Criminals wore a green triangle -green used to be the color of the police in Germany- for identification on their inmate's uniform.

2. The Nazis implemented a law for murder, in which they coined a new definition of what is considered to be murder. A murder is a crime that is comitted treacherously or sneakishly, or "with low morals". This is an offender-based description of a crime. This definition is still contained in today's murder law in Germany. Judges are forced to respect it, thereby neglecting "looking at the circumstances of each individual crime" [BBC article about the German murder law].

Here are a few key changes. Sources - this german article (that focuses on political oppression) and a book and the history of Munich's police in the Nazi era, that I read but don't have on hand now.

• already in Feb. 33, the so called "Schiesserlass" (shooting decree) guaranteed immunity for policemen who used deadly force against declared enemies of the state. An interesting question would be if this also protected police who killed ordinary criminals - I would guess so
• Members of SS, SA and Stahlhelm could be used as auxiliary police, these would also use this position to hunt political enemies
• The two Notverordnungen (Emergency decrees) declared some elements of the Weimarian Constitution null. This included limiting or aboplisching some rights like freedom of press, freedom of speech, right to rally and extended rights for the police with seizures, searches and arrests.
• So called "protective custody", which allowed the police to arrest and incarcerate without trial. This was intended against political enemies (and I think later Jews), but I recall reading that it was occasionally used against 'normal' criminals.
• Political police were separated from the ordinary police chain of command and placed under the central command of Himmler. Police in the Weimarian republic was a states matter, mostly. There were rivalries between the police branches, how they affected ordinary criminals, I don't know.
• Police were used to hunt for Jews in the occupied territories and conduct mass murders. The same policemen were occasionally rotated back into the Reich. In 'Ordinary Men' Christopher Browning describes one police battalion that conducts mass shootings, he describes how during the course of the war less and less of the men have qualms about murder of captured civilians. So I think it is safe to assume that those police behaved more brutally at home, too.

There are two other important changes for which I'd have to hunt for sources:

• Eugenics - the ideology that criminals have "bad genes" and thus rehabilitation or resocialisation would be a waste of effort was not invented by the Nazis, and did not die with them. But this mindset flourished in the Nazi regime and affected Judges.
• Anyone deemd "career criminal" could be incarcerated in a KZ. This would include petty crime like theft and prositution (Many inmates of the KZ in Ravensbrück where alleged prositutes). It is probably wrong to claim that these were generally used as Kapos, though that certainly happened in some camps
• Being "antisocial" could be reason for incarceration in a prison or KZ. The category "antisocial" was used for unemployed, vagrants and occasionally gypsies (even when not unemployed or vagrant).

All in all, biggest change from the perspective of an alleged criminal was that you were not only punished for commiting a crime, but for beeing a criminal, or 'antisocial'. It's worth asking how much of this was already there in the Weimarian justice system, and how much of this is there in whatever state you live in.