“Accessory to murder” is, in many jurisdictions, an easier charge to prove than “murder”.

If you want to go after someone for murder, you must provide the following

• the identity of an individual victim, if possible by name.
• the time and place of death for that individual victim
• the method of death for that individual victim
• proof that this death was intentional
• proof that the person being charged is ultimately responsible, as an individual, for that intentional death. Did they, for example, hold a gun to the victim’s head? Did they personally throw him onto electrified wire? Did they personally operate a gas van that this specific victim was gassed in on this specific day?

That’s...surprisingly difficult to pin down for Nazis being charged for roles in the deaths of millions. How do you find an individual victim in the crowd that you know you can prove as the accused’s direct fault?

Charging someone as an accessory has a much lower burden of proof. An accessory need only know that a crime has been committed, is currently being committed or is being planned to be committed in the future, and act in some way that helps the perpetrator (whoever that might directly be) get away with it. They do not have to be physically present, or directly participating, at the time of death to be an accessory. What did the accused know, and what can you prove they did with that knowledge?

This distinction allowed for many, many more cogs in the Nazi regime to be held accountable for their role in what the regime as a whole was doing.