Alarcon-Serrano v. INS, 220 F.3d 1116, 1119 (9th Cir. 2000) (immigration official must have "reasonable, substantial, and probative evidence" that noncitizen knew he was participating in illicit drug trafficking to support finding of inadmissibility under INA 212(a)(2)(C)(i), 8 U.S.C. 1182(a)(2)(C)(i)), citing Hamid v. INS, 538 F.2d 1389, 1390-91 (9th Cir. 1976); Lopez-Molina v. Ashcroft, 368 F.3d 1206 (9th Cir. June 2, 2004).