SAN JOSE -- The pastor of the Saint Frances Cabrini School and Parish resigned Monday, weeks after his defense of a convicted child molester at a parish festival infuriated parents and scandalized the Diocese of San Jose.

In announcing the resignation of the Rev. Lieu Vu, the diocese also released a letter written by a former diocese human resources employee permitting convicted pedophile Mark Gurries to participate and volunteer at parish and school events.

Gurries unveiled a copy of the letter Oct. 6 when a 19-year-old former student recognized him working the sound system at a parish festival, setting off a heated exchange between a group of parents and the Rev. Vu.

When parents expressed outrage and demanded Gurries be removed from campus, the pastor reportedly defended Gurries, saying he had a right to be there and should be forgiven.

The heated confrontation continued for five hours, ending when a Santa Clara County sheriff's deputy, who was working the festival as security, escorted Gurries off campus.

The letter on Diocese of San Jose letterhead is dated Nov. 15, 2010, and was not authorized or approved by Bishop Patrick McGrath or his top deputies, the diocese said Monday in a news release.

It wasn't clear how often Gurries volunteered at parish events in the two years since the letter was written.

The 51-year-old engineer, married to a former teacher at Saint Frances Cabrini, was convicted of "lewd and lascivious conduct" on a minor under 14 years old and sentenced on May 17, 2010, to a year in county jail. It wasn't clear Monday when he was released from jail, but he remains on probation.

Also unclear Monday was the identity of the employee who wrote and signed the letter and when that person left the diocese. Gurries directly requested the letter from that employee to "inform his probation officer of the Diocesan policies regarding volunteers," the statement said. He said he occasionally volunteered at the Saint Frances Cabrini school and parish and had a child who attended a local Catholic high school.

The letter informs Gurries that he could "continue to participate in parent functions" and "volunteer in parish and school activities that do not involve regular, unsupervised contact with children, youth or vulnerable adults."

But he was told he "would not be permitted to volunteer" in unsupervised activities with children.

According to the California Penal Code, sex offenders are forbidden from being on school grounds unless they have a letter of permission from a chief administrator. Gurries requested that waiver from the diocese and received it.

Parents had demanded accountability from the school and parish for weeks, but didn't get any answers until the story was first published by this newspaper.

While some parents at the church said Monday they were pleased by the pastor's resignation, they were still looking for answers into who authorized Gurries' mysterious letter.

"There's probably 200 people out there who want to know who signed it from the diocese, and who knew," said Vickie Devincenzi, a parish parent. "That's what I don't understand. Who said it was OK?"

John Borrelli, whose daughter Melanie was the one who spotted Gurries working at the festival, said the parish should have been more forthright from the start.

"If they would have been more forthcoming, or notified parents in 2010, or turned down his request ..." he said. "I'm sorry, there's no need to volunteer at our school. Why couldn't somebody have said that?"

On Sunday, Bishop McGrath apologized for "a failure at the diocese level" that allowed Gurries to be a volunteer.

In its statement Monday, the diocese said that McGrath is "taking immediate steps to adopt and implement the policies that registered sex offenders will not be able to volunteer under any circumstances."

A spokeswoman with the diocese said the Gurries letter was the only known letter written by the diocese on behalf of a sex offender.

Vu steps down after three years leading the San Jose church and will not be reassigned as pastor within the diocese, according to a diocese statement Monday evening. He will be replaced by the Rev. Monsignor J. Patrick Browne, who recently retired as pastor of the downtown San Jose's Cathedral Basilica of Saint Joseph.

Saint Frances parents like Michelle Moura said it was "a shame" to see Vu step down, because she believed he could have handled things better on the night of the festival.

"I liked him. He always knew people's names, and I think that personalized the community," Moura said. "I think it's been a big learning lesson for both the Catholic church and our community."

Borrelli and others, however, are still looking to learn more.

"It's sad because here was a pastor that me and my kids listened to him preach. I didn't want this to happen," Borrelli said. "Kids look up to the pastors. It's sad that it all came to this."

Contact Julia Prodis Sulek at jsulek@mercurynews.com or at 408-278-3409.