Judges investigating sentencing facts

1. Whether the Due Process Clause of the Fifth Amendment permits a sentencing court to personally assume an investigative and prosecutorial role, such as independently locating evidence, directing the amendment of the presentence report, and examining its own witnesses over multiple days to establish facts increasing a defendant’s sentence, when the government has declined to seek that increase, without violating the defendant’s right to be sentenced by a neutral and detached tribunal? 2. Whether, consistent with this Court’s decision in Burns v. United States, 501 U.S. 129 (1991), and the Due Process Clause, a sentencing court may reject a factual stipulation that was a material inducement to a defendant’s guilty plea, and find facts increasing the defendant’s offense level nearly sixfold, without providing notice more specific than boilerplate plea-agreement language advising that the court is not bound by the parties’ recommendations?