A very good question. Novak's column was published on July 14. It has since been determined that a routine request for investigation was filed by the CIA within a week (evidently this is common practice, the DOJ receives about fifty such requests a year).
However, the request was not "publicized" (read "leaked") until a week ago Friday (Sept 26) -- by which time Ashcroft had appointed an investigative team and an orderly investigation was already underway.
Too orderly for some, evidently...