But there doesn't seem to be any evidence of illegal activity. It's not illegal to be seen in someone's company, is it? And the woman is only "believed to be an associate of an illegal bookmaker", so presumably no evidence of that either.
There may well be nothing in it, as there was nothing in the Oval ODI between England and Pakistan, which the ICC was not merely quick to investigate, but also quick to announce to the world that an investigation was under way.
Then too, there was no evidence, but just the mere possibility, of illegal activity. If it is not illegal to be seen in someone's company, it was also not illegal to score certain number of runs in certain overs. And if the woman is only "believed to be an associate of an illegal bookmaker", the scoring pattern in the Oval ODI was only believed to be suspicious, that too by an English newspaper.
The credibility that the ACU of the ICC has is almost nonexistent; the least they can do is not be glaringly inconsistent.