Teensy point about panel 2. “Fräulein” has essentially been a dead word in German since the 90s or thereabout. It sometimes gets used ironically, but even that’s fading. Any woman old enough to be addressed with an honorific is addressed as “Frau.”

I also wanted to point out that Germany has a pretty strong mystery kids tradition. It’s imported–The Three Investigators from the US and The Five Friends from the UK–but both are popular, particularly as audio plays. The Investigators (Die Drei ???) are the bigger franchise by far; in fact, there’s so much that they must have long ago gone well past the original source material. The stuff Beate would have heard and/or read would likely have been homegrown.