Recommended reading - The Black Door, by Collin Wilcox (1967):

The Black Door

By Collin Wilcox.

ASIN: B0006BQEGW

Published by Dodd, Mead.

First published 1967.

ASIN: B0006BQEGW

Description:

A crime reporter with ESP tackles a double homicide. In a San Francisco apartment building, a young woman is found strangled beside a piano player with a broken neck. He's a nobody – a dreamer with little talent and no future – but she is Roberta Grinnel, daughter of one of the wealthiest men in the Bay Area. Stephen Drake, crime reporter for the "Sentinel," feels nothing when he looks at their corpses, and this is a troubling fact. For Drake is a psychic, and when his sixth sense fails him, that means more trouble ahead. As Drake tries to come to grips with his cosmic gift, the mystery of the heiress and the piano player becomes the hottest story in town. To keep his gig at the paper, Drake will call on every source he has – on this plane and the astral one – but knowing danger's lurking doesn't guarantee he can stay out of its way.