ssued no factual findings in this case, we review Castaneda's claim of breach of a nonprosecution agreement de novo. [FN241 FNI7. United States v. Moulder, 141 F.3d 568, 571 (5th Cir.1998); United Slates v. Rallis, 28 F.3d 1399, 1409 (5th Cir.1994); United States v. Fitch, 964 F.2d 571, 574 (6th Cir