It could have been Asia, Australia, Europe, North/South America.
Evil people are on every continent.
While evil people are to be found everywhere, Africa takes the word "atrocity" to a whole new level.
An informative read on this subject is David Van Reybrouck's Congo: The Epic History of a People (2010). This work catalogues the whole sorry story of the so-called Democratic Republic of Congo; one of unrelenting warfare together with unimaginable brutality.
This is in addition to the other ongoing and long running wars on the African continent - South Sudan, Darfur, Somalia, Nigeria, the Boko Haram insurgency to name just some - all of which are accompanied by numerous acts of extreme brutality.(Little of this, of course, ever gets mentioned in the news media)
Then in the 1980s, there was the campaign by the ANC in South Africa, in which the "Necklace" was used on suspected police informers. This device of torture was improvised out of an old car tyre, which was filled with petrol (gasoline), hung around the victim's neck, and then set on fire. It typically took about 20 minutes for the victim to die. A bloody humane way in which to dispose of someone!
Violence is never very far away in this district (e.g. last January, myself and several other workmates had to do a merry dance while dodging some shotgun pellets that were flying around during a gang altercation).
However, I haven't ever heard of anyone around here being "Necklaced"!