I think it is clear. There is also the way he answered. To initiate an inquiry, there has to be a complaint. They cannot just suddenly decide for themselves to investigate an industry sector. They cannot do that, it is impossible. Even if there were a complaint, they would have to go before a judge to initiate an inquiry. So there has to be a complaint. Someone has to tell them that there is something going on.
I will give you a concrete example: what happened in the four municipalities around Sherbrooke. Apparently, someone was periodically giving the order by phone to set the price at the pumps. There was a complaint, made under oath. With that kind of complaint, they were able to investigate.
Let's take another easy to understand example: price-fixing for the cost of oil refining. If it is true that every month, each company decides on the price of refining oil for that company, how is it that at the beginning of every month, prices at the pump do not vary? The refining is done at different refineries, but the prices at the pump are the same. If Shell decides that it is 22¢ and Petro-Canada decides that it is 10¢, how is it that the pump prices are the same every month?