Just to add ...
In a study done in Korea they found that in 47 out of 54 murder cases the killers knew the geographical area where they dumped the bodies.
In spontaneous murders (heat of the moment), the victims were more likely to be found far away - over 40km away.
In killings where murder was not the intended crime, but a result of the crime (perhaps murder following sexual assault is an example of this, or murder to gain money), the victims were more likely to be found within 30km of the crime scene.