Does an indictment need to be constructively amended?

We review de novo the question of whether an indictment was constructively amended. Pierce , 785 F.3d at 844. A constructive amendment is a per se violation of the Fifth Amendment, but significant flexibility in proof is constitutionally permissible, as long as the indictment provides notice to the defendant of the core of criminality to be proven at trial. United States v. D'Amelio , 683 F.3d 412, 417 (2d Cir. 2012) (emphasis and internal quotation marks omitted). Because the core of criminality ... involves the essence of a crime, in general terms, and excludes the particulars of how a defendant effected the crime, id. at 418 (internal quotation marks omitted), there is no constructive amendment when the proof at trial does no more than supply the particulars.