An elusive (but not totally isolated) tribe in Peru killed an outsider who was known to provide them help (bananas, pots and pans), and it's not clear why (probably he stopped providing help), this and a series of other violent episodes prompted a government team to set up nearby in hopes of interacting with them to try to prevent future violence. T here already exist laws preventing others from contacting them out of a fear of communicable disease.
Christian evangelists still interact with them, hoping to convert them, and it's pretty difficult to stop.
In the end, despite mutual communication, they couldn't find out why they were killing people, because once they start asking questions, the tribe packs up and leaves.
Their interactions outside of the jungle seem to be primarily for resources and when they are not provided with those, they get upset and leave, and/or take the resources forcibly.
One thing that wasn't clear to me from the article:
Do the Mashco (the isolated tribe) speak the same language as the Yine (the more assimilated tribal people)? And if so, do the people on the contact team (at least some of them) speak the Yine language and can consequently speak directly to the Mashco using essentially the same language?
This kind of contact situation can't help but be difficult and dangerous, but if the contact team and the contactee tribe have a mutually intelligible language that they can use, it seems like it would make things a lot easier, relatively speaking.
In the article, one of the Yine people who the team works with had a father who was half Mascho, but was abducted as a child and used as a translator, she learned the language from him.
> they believed I was a pishtaco, an evil person who had come to steal the oil from their bodies.
> in the sixteenth century, [...] some of the Spaniards, frustrated that their muskets and cannons rusted so quickly in the jungle humidity, were said to have killed Indians and boiled their bodies in iron pots, then used their fat to grease the metal.
Christian evangelists still interact with them, hoping to convert them, and it's pretty difficult to stop.
In the end, despite mutual communication, they couldn't find out why they were killing people, because once they start asking questions, the tribe packs up and leaves.
Their interactions outside of the jungle seem to be primarily for resources and when they are not provided with those, they get upset and leave, and/or take the resources forcibly.