10. The necessity for eliminating the little overlooked clues and loose threads
9. The false suspect
8. The cover up
7. The flight
6. The actual killing
5. The first irretrievable step
4. The opportunity
3. The plan
What is the murderer’s ladder without temptation? Every detective moves forward on the motive of the criminal, just as they count off their suspicions in that the suspect had the motive, means, and opportunity (fled the scene, resisted arrest, etc.).
This a professional murderer. The temptation is anticipated by the motive (the need for money), and the remaining ladder steps (at least to actual murder) are expected to be performed professionally (and even the problems that may crop up during and after).
How is the professional murderer distinct from the psychotic murderer? The professional may be psychotic; but the psychotic is not professional.
If the absence of temptation so closely hews to psychology, it could also be the hallmark of the romantic murderer. However, this would an obsessive, romantic murderer.