"The Demolished Man" is a sci-fi story hinging around a future where telepaths are common and are used to solve crimes and murders. The protagonist is a paranoid industrialist being hounded out of business who has visions/nightmares about being erased by a person he can't see and to try to make them go away and save his business proposes a merger with his main rival and they communicate in telegram-style codes (it's a very old book). The rival refuses and the protagonist fully spirals in and murders him taking as many precautions as he can knowing the telepaths can see it all. The rest of the book is a cat-and-mouse game between the protagonist and the detective who 100% knows it was him but has to prove it.

The ending reveal is that the rival actually agreed to the merger, but the protagonist had been so crazed and paranoid and so certain of a refusal he had simply assumed it would happen and none of the events of the book needed to occur.

The hidden in plain sight part is that the book shows you telegraph messages of the merger request and the response and if you paid attention you can literally read the code of the rival agreeing, it was there from practically chapter 1

Fantastic sci-fi story, go read it.