A shamen's role involves seeking to restore an imbalance, particularly in things to do with nature. Traditionally, as an example, many indigenous cultures believe that the animals in a forest have spiritual "owners". You cannot hunt and kill an animal without holding a ritual to obtain the owners permission and if you do you will fall ill and you must make amends, under instruction and supervision of the shaman who acts as the medium with the spirit.
The idea is to maintain the natural equilibrium, if you take - you give back. That is why, for forest conservation planning projects, indigenous groups are increasingly involved as important actors and their traditional sacred sites and management practices are respected.
In this case, I think it was a clever and sensitive move to bring the shaman in because of the respect he would inspire locally and the equivalent of the "fear of God" in case someone was harbouring information of any kind.
The waterfall could well be a sacred site.
Whether the discovery of Nora's body the following day had anything to do with this or was pure coincidence is anybody's guess.
