Are you refering to the slayings in Banyuwangi in 1998?

http://www.insideindonesia.org/edit62/jason.htm

Indonesia for all its modernisation is a place where ‘traditional’ magic is practised widely. It is known that almost all politicians have some kind of ‘backers’ and black magic is widely used to rid off oppositions or oponents. And these is widely used in all aspect of life. From seeking cures for sickness to seeking favors is love and work or worst getting rid of business competition.

Banyuwangi happens to be a place where it is a nest for such praticetioners (often feared) Hence after the fall of the ‘new regime’, revenge killings started, unfortunately good or bad suspected praticetioners were hunted.