An immigration court can draw an adverse inference from a noncitizen's assertion of the Fifth Amendment privilege against self-incrimination. Bilokumsky v. Tod, 263 U.S. 149, 154 (1923); United States v. Solano-Godines, 120 F.3d 957, 962 (9th Cir. 1997).  However, where government offers no evidence except respondent's silence, it is insufficient to meet its burden of proof by clear, unequivocal and convincing evidence, and the burden does not shift to respondent.  Matter of Guevara, 20 I. & N. Dec. 238 (BIA 1991).