Kroll is the forensic fraud company that has been appointed by the board to investigate any allegations. They are the one who set up the website so that staff can report any fraud or corruption.
Kroll guys investigate and pass on their findings to the board. Its up to the board then to act, such as pass onto the CID.
I am of the opinion that Kroll will investigate what they want but the proof will be if any high profile personnel are caught and prosecuted - and that will be the decision of the board (who knows who they may protect).