All the activity that reportedly happened at Air New Zealand offices were after the accident had happened, so how could any of that be attributed to the cause of the accident?
If it happened after the accident, why didn't it happen before, or two years later? Seriously? There's nothing suspicious about destroying documents, breaking in to houses, missing pages of notebooks that the recovering officer clearly remembers were in good condition?
You don't destroy documents if you've got nothing to hide.