The scheduled federal execution of a 10-year-old Kansas girl’s killer was back on track Friday after an appellate panel tossed a lower court’s ruling that would have required the government to get a drug prescription before it could use pentobarbital to kill the inmate. Questions about whether pentobarbital causes pain prior to death has been a focus of last-minute appeals for Keith Nelson, who would be the fifth person to die this year and the second this week in the Trump administration’s resumption of federal executions after a 17-year hiatus. All the executions by lethal pentobarbital injection have been carried out at a federal prison in Terre Haute, Indiana.