Assistant District Attorney Robin Godfrey told Common Pleas Judge M. Teresa Sarmina that boxed evidence was the property of the Police Department, not the D.A.'s Office, and that the defense would often not receive it.
The defense team asked Sarmina to vacate Williams' 1986 death sentence and grant him a new penalty hearing, during which a jury would hear the new evidence and render a sentence of death or life in prison without parole.
A ruling will be announced Friday morning, the judge said.
Williams, once a star quarterback at Germantown High, is scheduled to be executed next week for the 1984 murder of Amos Norwood, 56, a married father and active member of St. Luke's Episcopal Church.
Williams and accomplice Marc Draper, both 18 at the time, tricked Norwood into driving them to the darkened Ivy Hill Cemetery, where they beat him to death with a tire iron and wrench.
At trial, Williams testified that he had not been at the scene and that Draper and another man were the killers. Draper testified that he and Williams killed Norwood during a robbery.
But during this week's hearing, Draper, who is serving a life sentence for the murder, recanted his testimony and said Williams initiated the slaying out of rage at being in an abusive sexual relationship with Norwood. Draper claimed that he had lied at trial after being threatened by homicide detectives and coached by the trial's prosecutor, Andrea Foulkes.
Defense attorneys say the new evidence supports their theory that prosecutors covered up the real motive to get the death sentence they sought.
Defense attorney Billy Nolas said that when Foulkes told the jury Norwood was "a kind man" who merely offered the defendant a ride home the night of the murder, she "created a false, inaccurate impression for this jury."
"It's grown men with young boys - it's awful. And the jury should have heard that it was awful," said Nolas, who added that the prosecutions's case "stinks to high heaven."
Foulkes testified last week that she never told Draper to lie. She said she lacked evidence to tell the jury of a sexual link between Williams and Norwood.
Contact Mensah M. Dean at email@example.com or 215-568-8278. Follow him on Twitter @MensahDean.