I'm currently reading "Kabumpo in Oz" by Ruth Plumly Thompson, but when Eor called to me from the other room I thought he said "Columbo in Oz." Which got us imagining this ...
"Just one more thing I was wondering about. Wasn't Dorothy a brunette when she first arrived in Oz?" He wouldn't be investigating murders, but plot inconsistencies.
Now I wonder what those inconsistencies could lead to discovering...