Testimony in the trial of Monsignor William Lynn, 61, the priest accused of helping the Philadelphia archdiocese hide decades worth of priest sex abuse complaints in secret files, has shocked the jury.

The court heard this week how one priest joked about how hard it was to have sex with three boys in one week, after internal Catholic church documents were read in court for the first time.

The shocking testimony was revealed during Monsignor Lynn's trial, where he is the first Roman Catholic church official to be charged in the US for his handling of priest abuse complaints, and now faces charges of child endangerment and conspiracy.

According to the Daily Mail prosecutors are detailing allegations made against nearly two dozen priests since 1948 to show that Lynn and other church officials gave child abusers repeated employment in jobs that gave them access to children.

A detective read to the court internal church memos concerning one priest who allegedly had a 'rotation process' of boys spending time sleeping with him.

Jurors also heard shocking testimony of a 1992 complaint about a priest accused of molesting boys at a church-owned camp three decades earlier.

The allegations covered many decades, with junior counselors complaining in the early 1960's that a priest was on the prowl at night, molesting them in their tents. The priests late night activities were a well-known secret among teenage counselors for several years.

The documents read out at court show that that particular priest remained in his ministry, working at three archdiocesan high schools and serving as assistant superintendent of Catholic schools right the way through 2004.

Monsignor Lynn's defense lawyers are arguing that hat Lynn, who was secretary for clergy from 1992 to 2004, tried to address the problem. Jeffrey Lindy and Thomas Bergstrom, defending, had detectives confirm that Lynn interviewed both complainants and accused priests and sent the priests to a church-run hospital for mental health evaluations and treatment.

The defense counsel claim many of Lynn's efforts were blocked by the late Cardinal Anthony Bevilacqua and others in the Philadelphia archdiocese. Cardinal Bevilacqua died of heart disease on January 31, a day after he was ruled competent to testify at Lynn's trial.

The Washington Post reports that Monsignor Lynn supervised more than 800 priests as the secretary for clergy in Philadelphia from 1992 to 2004.

Prosecutors charge that he kept known abusive priests in parish work around children to protect the church’s reputation and avoid scandal. He faces up to 28 years in prison if convicted of conspiracy and child endangerment.

Monsignor William Lynn leaves the courthouse after a hearing in Philadelphia, March 14, 2011.REUTERS