was the source of the drugs. But below, appellant only argued that the evidence was Brady material because it was useful for impeaching the informant regarding his drug addiction, which had been established. An appellant cannot change his theory underlining an assignment of error on appeal. Ford v. Warden, 111 Nev. 872, 884, 901 P.2d 123, 130 (1995).

Moreover, as appellant himself points out, the theory he advances on appeal is inconsistent with his testimony at trial, and given that testimony, he cannot complain that the evidence was withheld, see United States v. Diaz, 922 F.2d 998, 1007 (2d Cir. 1990) (concluding that Brady was not violated where evidence at issue was within the defendant's knowledge), or that it was material, see Mazzan v. Warden, 116 Nev. 48, 66, 993 P.2d 25, 36 (2000).

Having considered appellant's contentions and concluded that they lack merit, we ORDER the judgment of conviction AFFIRMED.

, C.J.

Hardesty

J.

Parraguirre

J.

Douglas cc: Hon. Scott N. Freeman, District Judge Law Office of David R. Houston Attorney General/Carson City Washoe County District Attorney Washoe District Court Clerk SUPREME COURT OF NEVADA (0) 1947A