Comment by cafard

I did read one out-and-out crime novel by Azimov. You will not be surprised to learn that the victim was graduate student in chemistry, the murder occurred in a laboratory, and the plot twist turned on something known chiefly to chemists.

(I've forgotten the title--I read the book nearer 50 than 40 years ago.)

Edit: I see from Wikipedia that it was The Death Dealers, later republished as A Whiff of Death.