The way of death/demise or how someone dies are divided into 5 categories: suicide, being killed by another person, being killed by an animal, accident, or natural disease.
This is an important principle for investigating cases because if it was a death from someone else's act, it would be a criminal act.
To know the manner of death. It takes a lot of information both from the location and from the corpse itself, all that Baankjit has to do is listen to what the corpse is saying.