This study has been there for last 2 decades so far I know, it could be even older.

I also saw a movie in India (15 years ago) vaguely explaining this evolutionary behaviour and how humans imitate it.

Humans tend to carry the corpse of their loved ones just like the monkey carried its loved one. Some real life instances where human could not bear to spereate from the loved ones, they mummified their parent's or lover's body in their house for decades in ice box or underground inside the house until police breaks in after decades due to some tip.

Police and judges could not get head or tail on this case as is it a homicide or some psychological issue. Psychologists get back to this study and say primates do the similar thing of hanging around with loved one's corpse just like human's do. 

Bur devouring is next level!

Should be common in Cannibalistic tribes as part of their evolution!

Very stray insidents I have heard of cannibalism in human civilzation, I will not say zero, there were some news here and there!