In my view ,its not common.i noticed that most crimes in Nigeria are tied one way or the other to poverty or the need to excel even ritual killing.
But serial killing is a different proposition.
Cases where the suspect has a traceable pattern, sometimes leaves a signature of some sort,or when his caught his defence is that he was obeying an instruction from above.possibly doing the society a favor (killing prostitues)
Some researches have also shown evidence of abuse in childhood or some kind of stressor (Divorce,job loss,trauma) as the trigger for such dastardly behaviour.
In Nigeria our own ills are different but if there are cases at all am sure they are quite few,
what do you think.

Why the question, in the first place? Are you a serial killer or planning to be one? I am really curious about this poser.