I couldn’t find the right combination of search terms to provide a citation, but I’ve heard stories of plane crashes where locals took the flight data recorder or other critical pieces of evidence from the scene before officials arrived. Rewards had to be announced and paid out to get people to bring back parts so that investigations could proceed.
I don't have a link, but a similar story happened on top of a mesa near Moab, Utah, in the 1970s. Local climbers already knew routes to the top and hiked out with whatever they could carry before the feds could fully clear it.
https://www.theatlantic.com/international/archive/2014/07/fl...