Not sure how that would apply in this case. The murder has been sentenced, he gave information regarding how he disposed of the body ( several months previously), the landfill company was able to narrow down where the body could be ( assuming the murderer’s information was correct) and it was a very large area, the body would have been there for a significant time, with several tons more of garbage then of earth having already been spread out on top.
The authorities had decided to at least make an effort to look for the body, though there was little chance they’d be successful, now the search area has been shrunken down to a small portion based on the tribal elder’s ceremony & findings.