Yes, but what constitutes a fair trial?The crucial point is whether they were sentenced to death in a fair trial.
The scene: Western Poland, September 1939.
A squad of German soldiers, led by a sergeant, bring a 15-year-old Polish boy before their company commander.
Sergeant: "Herr Hauptmann, we found this boy sneaking around our positions. We are sure he was trying to commit sabotage".
Captain: "What grounds have you for thinking he was trying to commit sabotage?"
Sergeant: "Well, he is a Pole and must be hostile to us, always looking for a chance to do us harm. Also, we found a paper on him showing he is a member of Harcerstwo, the Polish Boy Scouts. The members of Harcerstwo are known to be fanatically hostile to us, and are linked to the National Democratic Party, which we all know is extremely anti-German. I reckon the only reason a member of Harcerstwo would be hanging around our positions would be to commit some sort of sabotage".
Captain (to the boy): "What were you doing around our positions? Were you trying to commit sabotage?"
Polish Boy: "No, Herr Hauptmann. I was just trying to get home".
Captain: "On the basis of the evidence, I find that this boy was attempting to commit sabotage against the German armed forces, an illegal act, since he is not a legitimate member of the Polish armed forces. Take him out and shoot him".
Did this Polish boy receive a fair trial? A German officer heard the evidence against him, consisting of the suspicions of the German soldiers who caught him, let the boy have his say, and reached a decision based on the evidence, namely the boy's activity which was rendered suspicious by his background.
A number of participants in this Forum, including the moderator on occasion, have postulated a right, under the international law of the time, for the civilian population of an invaded country to form militias and fight with weapons in hand against the invading armed force. If that right indeed existed, and it has been claimed for Polish and French civilians, then presumably it existed also for German civilians, and the Hitler Youth might be considered to be a militia, particularly if the German Government had given its members the status of combatants, as I think it did in the final stages of the war.It has always been legal to execute inhabitants of occupied territories for participating in hostilities as francs tireurs and espionage (aka 'war treason').