I think they think she washed ashore and is now buried underneath all the rocks.
Actually looking at it I'm wondering if Parsee is saying if they were to dam the river then Kyouko would be easy to find cause she would just be laying in the river bed. I might be wrong but that would explain why Kogasa is asking how many rocks.
Actually looking at it I'm wondering if Parsee is saying if they were to dam the river then Kyouko would be easy to find cause she would just be laying in the river bed. I might be wrong but that would explain why Kogasa is asking how many rocks.