Philadelphia, Pa., Jul 28, 2016 / 06:01 am (CNA/EWTN News).- The Pennsylvania Supreme Court let stand July 26 a ruling that prosecutors in a Philadelphia priest’s trial used prejudicial evidence related to clergy sex abuse. Philadelphia’s district attorney must now decide whether to re-try Monsignor William J. Lynn. The priest was not accused of sexually abusing children. However, he was convicted on one felony count of child endangerment for failing to protect children from an abusive priest, and was sentenced to three to six years in prison.

Msgr. Lynn, now 65 years old, had served as the Philadelphia archdiocese’s Secretary for Clergy from 1992 to 2004. As such, he was responsible for investigating priests accused of abuse. He was the first Catholic official convicted for a supervisory role over priests accused of abusing children. That trial could be revisited, or the priest could be released for good.

In December 2015 the Superior Court had ordered a new trial for Msgr. Lynn. It agreed with his lawyers that the prosecutors had wrongly tainted the judgement of the jury by using historical evidence of the Church’s handling of sex abuse, the Philadelphia Inquirer reports. Some of the two dozen case histories dated to the 1940s.

In the priest’s 2012 trial, prosecutors used the history in an effort to show the priest was part of a dominant culture in the archdiocese. The judge at the trial allowed it as background on the grounds that jurors could understand the context and the culture in which Msgr. Lynn was operating. The priest’s lawyers said the evidence was prejudicial and inflammatory and drove the jury toward a guilty verdict.

The charge against Msgr. Lynn stemmed from his response to the case of Edward Avery, a now-laicized priest serving a jail sentence for abusing an altar boy during the 1990s. Prosecutors said Msgr. Lynn had reassigned Avery to live near a church school, despite having substantiated a claim of abuse against the priest. After reassignment, Avery sexually assaulted a 10-year-old boy in 1999.

Philadelphia district attorney Seth Williams had appealed the December 2015 decision that ordered a new trial for Msgr. Lynn. The district attorney must decide whether to hold another trial for the priest, who has served half his sentence. He will be paroled Oct. 16. Pennsylvania inmates are typically eligible for parole after they serve their minimum sentence. His attorney has sought bail of $250,000.