The motion by Shawn Nolan, a member of the defense team from the Federal Defender's death penalty unit, contends that Castille has declined to recuse himself in previous cases his office handled when he was district attorney.
"Should Chief Justice Castille decline to recuse himself, this motion [should] be referred to the full court for decision and that the full court direct Chief Justice Castille's recusal," the defense motion reads.
Art Heinz, a spokesman for Castille, said the justice would have no comment on the motion.
Officials of the District Attorney's Office were not immediately available for comment.
Today's defense filing was in response to a petition to the state's high court by city prosecutors to set aside Friday's ruling by Common Pleas Court Judge M. Teresa Sarmina, who stayed Wednesday's scheduled execution of Williams, 46.
After two days of hearings, Sarmina ruled that the integrity of Williams' death sentence had been undermined because the trial prosecutor and police withheld from Williams' lawyer evidence of the victim's sexual abuse of teenage boys.
Williams, then an 18-year-old Cheyney University freshman and football star from Germantown High School, was sentenced to death for the June 11, 1984, murder of Norwood, a Germantown church volunteer whose body was found in a cemetery, head bludgeoned with a tire iron and then set afire.
Prosecutors alleged that Williams and admitted accomplice Marc Draper, then also 18, killed Norwood during a robbery, and Williams did take Norwood's car, cash and credit cards to gamble in Atlantic City.
At trial, Williams testified that he did not know Norwood and was not there when Draper and another person killed Norwood.
But in her ruling granting a stay of execution, Sarmina said she believed Draper's recantation statement that police and prosecutor ignored his first account of the Norwood killing: a rage-based attack fueled by five years of sexual abuse by Norwood and other men.
Had prosecutors made that information available to the defense attorney to use at trial, Sarmina said, the jury might have decided to spare Williams' life and sentence him to life in prison without parole.
Contact Joseph A. Slobodzian at 215-854-2985, firstname.lastname@example.org, or @joeslobo on Twitter.