CHROMATOGRAPHY
As part of solving the case of the blackmailing of Santa Claus by an unknown elf who was angry about Santa's reorganization plan, we used a simple chromatography test to identify the author of one of the anonymous notes.
We obtained time sheets signed by the two prime suspects on the same day a note was written to Santa.
Both were written in black ink and looked the same.
BUT....
When we dipped the signatures in water, only one matched the note.

Chroma1.jpg
Yuley Gooch's signature


Chroma2.jpg
Signature from the anonymous note
Chroma3.jpg
Chromatography test



Chroma4.jpg
Case closed!