What is your source for that information?
It doesn’t matter. The FBI or the Sheriff or the NM State Police should have secured that site with armed guards. Unless of course they were the ones destroying the evidence.
Did you guys see this? They left a lot of the evidence behind.
Common sense and logic.
If the FBI or CIA had wanted to destroy the evidence, they would have done a much better job.
Remember the other incident similar to this one where the 'locals' found a 'camp' that had an underground 'chamber' that they suspected children were being kept captive ?