I wonder if the long, inexplicable delay in finding the crash site was not the start of a cover up. They should have - and maybe did - find it within a hour of first light. Then, they got all the evidence and black boxes - this took about a day. Then, they announced they had finally found it.
This is speculation on my part. But it does fit the time line.
The waters there is 10,000 feet deep. Even if they did find where it crashed, it would be impossible to find the black boxes that quickly.
Sounds a bit like conspiracy theory.