Philadelphia (CNN) -- Attorneys in the child sexual abuse and conspiracy trial of two Philadelphia priests debated Monday over which potential witnesses jurors would be allowed to hear regarding a third defendant who pleaded guilty to molesting boys just days before opening remarks.
Defrocked priest Edward Avery of the Philadelphia Archdiocese pleaded guilty to involuntary deviate sexual intercourse and conspiracy to endanger the welfare of child after admitting that he sexually assaulted a 10-year-old altar boy during the 1998-1999 school year. Avery, 69, was sentenced to two-and-a-half to five years.
The Rev. James Brennan is accused of attempted rape of a 14-year-old, and Monsignor William Lynn is accused of covering it up. Lynn is the first high-ranking church figure charged with child endangerment for shuffling predator priests from parish to parish.
Lynn is accused of knowingly allowing Avery and Brennan access to children despite allegations of sexual abuse of minors.
Both have pleaded not guilty.
Although jurors were told Avery is no longer on trial, they have not been told why. His guilty plea does not require him to testify.
Prosecutors said Monday the former altar boy whom Avery admitted molesting in the church sacristy is scheduled to take the witness stand this week. He was abused six years after the archdiocese learned Avery had abused someone else.
Assistant District Attorney Patrick Blessington argued that if Lynn's defense attorneys "attacked the creditability" of the witness, the Commonwealth would be allowed to tell the jury Avery pleaded guilty.
"Monsignor Lynn put a powder keg out there," Blessington said while the jurors were out of the courtroom.
Defense attorney Jeff Lindy dismissed that claim, arguing that allowing jurors to hear Avery's plea or having other witnesses alleging abuse after Lynn left his post as secretary of clergy put his client at a disadvantage.
"It doesn't shine any light on what Monsignor Lynn knew," he said. "Things he didn't know about could not possibly go to his state of mind."
After listing to both sides in open court, Common Pleas Court Judge M. Teresa Sarmina suggested that perhaps prosecutors call Avery to the witness stand. Sarmina delayed ruling on also allowing additional victims to testify against Avery.
"I wouldn't be surprised if there were many, many more," she said. "Why didn't they come forward until 2010? There's a myriad of reasons. It takes a lot to come forward."
Jurors also heard the remainder of testimony about a former priest accused of abusing a 15-year-old boy for three years, beginning in 1984, engaging in "everything sexually two men can do."
While in treatment, the priest admitted to having a sexual relationship with the teen. He also described a number of incidents where he was the victim of sexual abuse, including a time when he was tied down by several seminarians who tried to rape him and that a friend came to his aide. He also revealed another incident when he was 10 and made to "kiss" a group of boys' genitals.
Prosecutors also plan to call Monsignor Kevin Quirk to the witness stand. A West Virginia judge ordered Quirk to testify, noting he was a "necessary and material witness," according to court documents obtained by CNN. Quirk presided over Brennan's 1996 canonical trial for an alleged sexual abuse of a minor.