I ask again, what is it that needs investigating?
There were injuries to passengers and damage the the aircraft, so an investigation is quite appropriate.
Eye witness accounts are notoriously unreliable, and newspaper reports even more so. The NTSB certainly would not rely on the former and would not even consider the latter. So until they investigate they have no way of knowing what happened. Had the press report claimed that the "Fasten Seat-belts" sign was OFF would you still assume the story was correct and that no investigation was necessary?
Even if the report in the paper is complete and accurate in every respect it does not provide a full understanding of what happened, only a very partial one.
Edited: to provide a more helpful response.