concurring:
I am pleased to concur in the majority opinion. I offer this short comment to highlight the importance of this case for prosecutors and criminal defense counsel handling suppression motions before United States Magistrate Judges in felony cases, a phenomenon seemingly on the rise in some districts. Although district judges conduct de novo review of magistrate judges’ reports and recommendations, magistrate judges are the first-level fact-finders, and, absent an evidentiary hearing “do-over” by the district judge, the exclusive authority on demeanor evidence and credibility assessments. See ante at 200-01 & n. 4. The lesson here is simply that, as always, counsel need to pay heed to the identity of the factfinder and the relative competence, in the hierarchy of judicial *204review, of who has the last word on findings regarding the “who, what, when, and where,” cf. United States v. Santiago, 268 F.3d 151, 156 (2d Cir.2001) (Sotomayor, J.), which underlie consequential judicial determinations.