As other folks have mentioned it would depend on the type of witch.
In anthropological terminology a 'witch' differs from a wizard in that they do not use physical tools or actions to curse; their maleficium is perceived as extending from some intangible inner quality, and the person may be unaware that they are a 'witch', or may have been convinced of their own evil nature by the suggestion of others.
That there would suggets to me a Sorceror rather than a Wizard.
Some of the healers and diviners historically accused of witchcraft have considered themselves mediators between the mundane and spiritual worlds, roughly equivalent to shamans. Such people described their contacts with fairies, spirits or the dead, often involving out-of-body experiences and travelling through the realms of an 'other-world'. Beliefs of this nature are implied in the folklore of much of Europe, and were explicitly described by accused witches in central and southern Europe. Repeated themes include participation in processions of the dead or large feasts, often presided over by a female divinity who teaches magic and gives prophecies; and participation in battles against evil spirits, 'vampires' or 'witches' to win fertility and prosperity for the community.
If you go with the ascribed stuff above then I would say a Cleric or Druid would be a good source.
