How do you test for cyanide?
In cases where no suspicious substances are observed in the scene of the death, the presence of cyanide in the victim's body can be confirmed chemically using a colorimetric test, followed by a laboratory analysis using a gas chromatography–mass spectrometry (GC-MS).
Forensic Research Extends Detection Of Cyanide Poisoning
https://www.shsu.edu/~pin_www/...cyanideresearch.html
Here you go Mits.