I fail to see how one company can be accused of running a price fixing scam on it's own, others would surely need to be complicit for it to work. The way I'm seeing this is that two directors tried to be a bit crafty but weren't very clever about it. By sacking the two involved the company has attempted to distance itself from their actions and refers to it's own written rules as evidence these two acted without company authority.
The investigation will surely be looking at how far through the board and senior management of the company this was being perpetrated and act accordingly.