Incest, cannibalism, necrophilia
 

There's various sources that have the same story, but none of them are highly regarded? Shrug. Enjoy:

http://www.dailymail.co.uk/news/arti...Argentina.html

Step brother and sister accused of being lovers 'shot dead their parents, fed them to their dogs and were only caught after a pelvis bone was found in a bucket in the garden' in Argentina