I think it was the same day that Ashcroft testified (Wednesday), but it might have been after Thursday's testimony. Kean and the other co-chair were being interviewed (they gave a presser) and the issue of Gorelick having authored the memo was brought up. In response to that, Kean said something to the effect that people should "stay out of our [the Commission's] business."
The comment did not occur as part of the scheduled proceeedings.