Ruiz-Vidal v. Gonzales, ___ F.3d ___, 2007 WL 113940 (9th Cir. Jan. 18, 2007) (DHS failed to establish unequivocally that the particular substance noncitizen had been convicted in state court of possessing in 2003 was a controlled substance as defined in section 102 of the Controlled Substances Act, for purposes of that conviction serving as a predicate offense for removal).