(Newser) – University of Illinois graduate student Yingying Zhang disappeared in June. The Chinese woman's body has not been found, but federal prosecutors believe that Brendt Christensen is responsible for her murder—and they announced Friday that, with Attorney General Jeff Sessions' blessing, they will pursue the death penalty in their case against him. The Chicago Tribune looks at just how rare a thing such a conviction and sentence would be. Illinois did away with the death penalty in 2011, and its use in federal court is far from commonplace. More on the case, the move, and the growing allegations against Christensen:

• The Tribune reports the last instance of the federal sentence being imposed in Illinois court was in 2005, when Dr. Ronald Mikos was found guilty of murdering a one-time patient who was cooperating in a Medicare fraud trial against him. The Supreme Court declined to hear his appeal in 2009, the AP reported at the time, but he still awaits execution.