Many serial killers avoided detection/capture as long as they did by moving around. Thus:
- Get victim from place A.
- Kill victim at place B (some distance from A)
- Dump body at place C (also some distance from A & B).
If the victim was a street person, for example, the body may never be identified and thus the killer’s connection to it may never be discovered.
Also - work alone, pay in cash, and don’t leave anything behind.