The argument is part of the attorneys' most expansive attempt to refute or derail the case against Lynn before his March trial. In the 70-page court filing, they claim that prosecutors have egregiously misapplied the law, wildly misstated facts, and unfairly portrayed their client.
The document sets the stage next month for a hearing and ruling that both prosecutors and defense lawyers have acknowledged could shape the outcome of the case.
Lynn, 60, faces charges of conspiracy and endangerment stemming from his role as the secretary for clergy under Cardinal Anthony J. Bevilacqua. At the time of his arrest in February, he was the highest ranking church administrator nationwide to be charged with covering up child sex abuse by priests.
Prosecutors say Lynn endangered children when he recommended the Rev. Edward V. Avery and the Rev. James J. Brennan for parish assignments in the 1990s that gave them access to children despite previous complaints or signs of abusive behavior.
Both men are accused of molesting boys in those posts. Facing trial with them on similar charges are the Rev. Charles Engelhardt and Bernard Shero, a former teacher at a Catholic elementary school in Philadelphia.
Common Pleas Court Judge M. Teresa Sarmina has barred the lawyers and defendants from publicly discussing the case. So it has largely been left to unfold in brief pretrial hearings and court filings.
In one motion, prosecutors asked the judge to let them introduce evidence at trial about how Lynn handled abuse sex-abuse allegations against 27 other priests between 1992 and 2004, when he was secretary for clergy.
They contend that only by understanding the church's response over years will the jurors be able to recognize a conspiracy and conclude that Lynn's recommendations for Avery and Brennan were part of a "well-established, deliberate, orchestrated plan" by archdiocesan leaders.
"What might look like an innocuous transfer, an accidental omission, or a mistake in judgment in a single case can only be understood as intentional when it is repeated over and over in the handling of other abusers," Assistant District Attorney Mariana Sorensen wrote.
In their response Monday, Lynn's lawyers said Sorensen's motion was "replete with misstatements, mischaracterizations, and inaccuracies."
They noted that Lynn's job included overseeing personnel issues for 800 archdiocesan priests, and that responding to sex-abuse allegations was a small part of his job and not a task for which he was trained.
"Overall," their reply said, "Msgr. Lynn has exercised good judgment in handling the priests in the Archdiocese of Philadelphia that have been accused of inappropriate or abusive conduct."
Repeating an assertion they have made since Lynn was charged, the attorneys accused prosecutors of overstating Lynn's authority. Never, they said, did he have the power to place or assign priests.
"Only the archbishop could do so, and Msgr. Lynn gave a vow to obey the directives of the archbishop on his ordination day," the motion states.
Bevilacqua has not been charged in the case.
Even if one were to accept that Lynn had unilateral power, his lawyers say, he didn't use it in many of the 27 cases cited by Sorensen as examples of his "prior bad acts." Many, they contend, involved complaints against priests filed before Lynn became the secretary for clergy or resolved after he left.
Others were allegations - like possession of child pornography - that they assert cannot fairly be used to show how he or the archdiocese handled child-abuse claims.
Lynn's lawyers say Avery's case is the only one in which Lynn recommended a parish placement for a priest who had been previously accused of abuse. In the early 1990s, a former altar boy accused Avery, then a parish pastor in Mount Airy, of molesting him in the 1970s.
After six months of inpatient treatment, Avery was assigned as a chaplain at Nazareth Hospital in Northeast Philadelphia and allowed to live and celebrate Mass at St. Jerome's Church. It was there, prosecutors say, that he, Engelhardt and Shero molested the same altar boy. Prosecutors say Lynn's conduct effectively enabled the assaults.
But Bergstrom and Lindy also questioned the legal basis for the charges. They say Lynn can't be tried for child endangerment because he never had direct supervision over a child during his tenure as secretary for clergy.
Contact staff writer John P. Martin at 215-854-4774, firstname.lastname@example.org, or @JPMartinInky on Twitter.