The Breaker: Book 1, by Jack Kost.

A neo-noir thriller.
Themes: crime, detective, thriller, suspense, sociopath, narcissistic abuse, psychopath, suspense, mystery, murder.

Back cover blurb:

How do we choose our path and purpose in life?
What makes us who we are?
When Seth Egan starts working as a private detective, he knows he’ll make enemies.
It goes with the territory.
As Seth works on a murder case and hunts down the killers, he becomes the target.
Some people have no conscience, shame, empathy, or remorse.
To get their own way, to get what they want, to take everything, they will do anything.
Even murder.
In the end, they will drag you down to hell with them.
Sometimes, our enemies are those closest to us.