When did Powell's description get reported?

[BettyO]

As far as I know, it was initially thought that the assailant was John Surratt, Jr. Of course, William Bell had gotten a good look at Powell (and could describe him and the timbre of his voice) extremely well. Likewise, Fanny Seward, although she refused to identify him for fear of "causing his death." Robinson could also probably identify him, although the room was somewhat in shadow with the lamps turned low. Fanny did get a glimpse of Powell out in the hall arguing with Fred Seward, as did Robinson.

I've always wondered if Powell knew about Fanny's refusal....