From my understanding, I don't think it would be at my discretion.
If an investigation has begun, in my opinion, it should continue. What it will likely mean—and this is putting on my lawyer's hat—is that if there are findings of credibility in relation to the investigation, some interviews might have to be held again in light of the fact that the commissioner making those findings would at least have to have met the individuals at issue.
Stopping an investigation and having to start from the beginning, I doubt it.