All 3 Uses

red herring
in
The Curious Incident of the Dog in the Night-time
(Edited)

Either that or it was a Red Herring, which is a clue which makes you come to a wrong conclusion or something which looks like a clue but isn't.
Chpt 59

red herring = a diversion intended to distract attention from the truth
I like The Hound of the Baskervilles because it is a detective story, which means that there are clues and Red Herrings.
Chpt 107 *

red herrings = diversions intended to distract attention from the truth
And these are some of the Red Herrings Sherlock Holmes and Watson are followed when they are in London by a man in a coach with a black beard.
Chpt 107

red herrings = diversion intended to distract attention from the truth

Definitions:

(1) (red herring as in: distracted with a red herring)
a diversion intended to distract attention from the main issue
(2) (meaning too rare to warrant focus)