Your opening request practically describes my book Fluids. As well as being a serial killer fanatic, I did a lot of research on my book regarding the differences between sociopaths and psychopaths with the intent of creating a character with the correct traits. https://www.amazon.com/Fluids-Ben-Clayton/dp/B08C8Z8MJM

My friend published a book about two serial killers, and it focuses on their perspectives, motivations, and psyche. It's a fast-paced read and is worth checking out. Give an independent creator some love. Get your hands wet in "Fluids" here: https://www.amazon.com/Fluids-Ben-Clayton/dp/B08C8Z8MJM