Review of planted evidence

1. Whether credible allegations that government agents fabricated and planted evidence in a criminal prosecution — conduct that, in civil proceedings, constitutes “fraud on the court” exempt from any time limitation under Hazel-Atlas Glass Co. v. Hartford-Empire Co., 322 U.S. 238 (1944), and Federal Rule of Civil Procedure 60(d)(3) — may be denied judicial review based on procedural timeliness requirements when the government actively concealed its own fraudulent scheme. 2. Whether due process and fundamental fairness permits a court to deny post-conviction relief based on untested government declarations from witnesses who never testified in the case, without affording the defendant any opportunity for adversarial testing of their assertions, thereby reducing post-conviction review to a non-adversarial proceeding.