The Federal Public Defender appointed to represent Mariano Diaz has moved for leave to withdraw and has filed a brief in accordance with Anders v. California, 386 U.S. 738, 87 S.Ct. 1396, 18 L.Ed.2d 493 (1967), and United States v. Flores, 632 F.3d 229 (5th Cir. 2011). Diaz has filed a response. We have reviewed counsel’s brief and the relevant portions of the record reflected therein, as well as Diaz’s response. To the extent that Diaz challenges the conduct of counsel at sentencing, the record is insufficiently developed to allow consideration at this time of his claim; such a claim generally “cannot be resolved on direct appeal when the claim has not been raised before the district court since no opportunity existed to develop the record on the merits of the allegations.” United States v. Cantwell, 470 F.3d 1087, 1091 (5th Cir. 2006) (internal quotation marks and citation omitted). We concur with counsel’s assessment that the appeal presents no nonfrivolous issue for appellate review. Accordingly, counsel’s motion for leave to withdraw is GRANTED, counsel is excused from further responsibilities herein, and the APPEAL IS DISMISSED. See 5th Cir. R. *392 42.2. Diaz’s request for appointment of new counsel is DENIED.