My farther was attacked by prankers, from skype account. Unfortunatelly we dont know skape account name. But i think you can trace the call by calling party number. Also prankers calls on mobile phone, that means that they use credit cards with names.
Anyway, i will be glad to hear any methods to recognize the persons who call.
By the way, all neccesary requests were sent to our local police station, but still no solution.