By Dave Warner

NEW YORK, June 6 (Reuters) - A Philadelphia jury ended its fourth day of deliberations on Wednesday without reaching a verdict in the child sex abuse trial of a Roman Catholic monsignor, the highest-ranking U.S. clergyman to stand trial in the church's wide-ranging pedophilia scandal.

Monsignor William Lynn, who for 12 years as secretary of the clergy supervised hundreds of priests in the Philadelphia Archdiocese, is accused of conspiracy and child endangerment.

If convicted on all charges, he faces the possibility of 21 years in prison.

The jury in Common Pleas Court before Judge M. Teresa Sarmina began deliberating on Friday after hearing 10 weeks of testimony in the closely watched trial, which has rocked the nation's sixth largest archdiocese, with 1.5 million members.

The panel was scheduled to resume deliberations on Thursday morning.

Prosecutors say Lynn, 61, covered up child sex abuse allegations, often by transferring priests to unsuspecting parishes.

Lynn's motive was to avoid scandal and any potential loss of money for the church, they argued. His job was to supervise 800 priests, which included investigating sex abuse claims, from 1992 to 2004.

The defense said Lynn tried to handle documented cases of pedophile priests, making a list in 1994 of 35 accused predators and writing memos to suggest treatment and suspensions. He was hampered because he could only make recommendations to the head of the archdiocese, Cardinal Anthony Bevilacqua, who died in January at age 88, the defense said.

Thousands of cases of child sex abuse by priests have come to light in Europe and the United States in recent decades. More than 10,000 allegations of child sex abuse were brought against U.S. priests between 1950 and 2002, according to a report commissioned by the U.S. Conference of Catholic Bishops.

The Philadelphia jury is also deliberating the fate of the Reverend James Brennan, 48, who is charged with child endangerment and the attempted rape of a 14-year-old child in 1996. (Editing By Ellen Wulfhorst)

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  • W. Jeffrey Paulish

    Paulish, a Catholic priest, was charged with molesting a 15-year-old boy after police say he was "caught in the act." The 56-year-old priest was found in a car with the pantless boy on the campus of Penn State University. <a href="http://www.huffingtonpost.com/2013/09/22/w-jeffrey-paulish-caught-with-pantless-15-year-old_n_3971522.html" target="_blank">Read more</a>

  • Rev. Robert Van Handel

    FILE - This undated file image provided by State of California Department of Justice shows former priest and convicted sex offender, Robert Van Handel, who was molested as a student at St Anthony's seminary school and then returned there as a priest where he molested boys in the choir. (AP Photo/California Department of Justice, File)

  • Monsignor William Lynn

    FILE - In a Tuesday, March 27, 2012 file photo, Monsignor William Lynn leaves the Criminal Justice Center, in Philadelphia. Lynn, accused of moving predator-priests to unwitting parishes, testified Wednesday, May 23, 2012 that he had no authority to make priest transfers. Lynn says he could only remove a priest who admitted abusing a minor. Lynn says he otherwise made recommendations for the cardinal. Lynn is testifying in the ninth week of his child-endangerment and conspiracy trial. (AP Photo/Alex Brandon, File)

  • Rev. James Brennan

    The Rev. James Brennan allegedly molested a 14-year-old boy in 1996. The accuser testified in court that the sexual abuse led to drug addition, mental illness, crime and suicide attempts.

  • Cardinal Anthony J. Bevilacqua

    The late Cardinal Anthony J. Bevilacqua ordered aides to destroy a list with the names of priests accused of sexual abuse, according to church documents revealed during the trial of Philadelphia's Monsignor William Lynn.

  • Ex-Priest John Fiala

    This Nov. 18, 2010 photo provided by the Dallas County Sheriff's Department shows John Fiala. Fiala, a former Roman Catholic priest charged with sexually abusing a teenage boy in 2008 in his rural Texas parish is now accused of plotting the alleged victim's murder, authorities said. Fiala was found guilty of the plot in May of 2012. (AP Photo/Dallas County Sheriff's Department)