CHICAGO (AP) — Lawyers for a former physics student accused of kidnapping and killing a University of Illinois scholar from China intend to ask the presiding federal judge to recuse himself in the death penalty case.

A two-page filing in central Illinois federal doesn’t spell out why Brendt Christensen’s attorneys think Colin Stirling Bruce should step aside. The document filed Wednesday requests he let them submit a recusal motion under seal.

Defense attorney Robert Tucker declined comment Thursday.

Prosecutors announced Jan. 19 they’ll seek capital punishment, saying Christensen allegedly tortured Yingying Zhang before killing her.

The defense said in another filing they’ll need until mid-2019 to prepare for trial, including to possibly research of Christensen’s genealogy and prenatal care to shed light on his mental state. Prosecutors want the trial this October.