Apocalypse by Harry Lorayne Volume 12, Number 6 June 1989 Page 1655 et seq.
Personal Comment: I'm not a great fan of riffle shuffles... but I do see how this can fool people if properly executed. The original handling used a face up card as the locator card. This uses another fairly common method. But I think this is slightly better as there is no chance of a face up card appearing in the riffle shuffle.