Advocates for victims of clergy sex abuse are bracing for what they say is certain to be stunning findings out of the most current investigation into abuse across six Catholic dioceses in Pennsylvania.

One of those advocates, Shaun Dougherty, himself a childhood victim of sexual abuse by a priest, warned that the findings expected out of the grand jury investigation could be extremely troubling.

"There's some graphic things coming," Dougherty told PennLive during a phone interview from his home in New York. "If their report reflects the reports I'm hearing, yes some parts are going to make the Altoona-Johnstown report look like Disney World. This is huge."

Dougherty, who is part of a social media network of victims of clergy sex abuse, has met with scores of victims, including individuals who have testified before the current grand jury investigation.

Empaneled in 2016, the grand jury is investigating allegations of child sexual abuse among church officials and priests and laypeople in six dioceses: Harrisburg, Allentown, Erie, Scranton, Greensburg and Pittsburgh.

The grand jury is expected to release its findings as early as May.

Meanwhile, the Diocese of Harrisburg posted a letter on its website Monday noting that it's committed to the safety of children, noting that April is Child Abuse Prevention Month.

"We take very seriously the protection of youth in all Church-related activities and programs. We are working to make the Catholic Church one of the safest institutions in the country," the letter said.

"To report the suspected abuse of a minor, you must notify both law enforcement and the Church. First, call the PA Child Abuse Hotline at 1-800-932-0313. To report suspected abuse of a minor by a Church official, employee or volunteer, no matter when it happened, call the diocesan toll free hotline at 1-800-626-1608."

You can read the entire letter at this link.

Despite the tone of conversations he has had with victims, Dougherty said testimonies likely were not tell-all accounts of past abuse.

Dougherty, whose testimony to law enforcement agents was included in the 2016 grand jury investigation report of the Altoona-Johnstown Diocese, said victims often withhold information.

"I don't know if I'm ever going to fully disclose what happened to me," said Dougherty, who was 10 and a fifth-grader at St. Clement School when he was abused by George Koharchik, a pastor at the school.

"Those reports...they are graphic..but I don't know if everybody has disclosed everything. Who the hell wants to share these things with even family members or friends, let alone the public. Let alone the official state attorney general. Let alone go to the Capitol constantly and stand on the steps in front of 50 cameras?"

In the Altoona-Johnstown report, investigators found that hundreds of children had been sexually abused over a period of at least four decades by priests or religious leaders in the diocese. The findings revealed a troubling history of diocesan superiors concealing the child abuse as part of an effort to protect the church's image.

An attorney who has for nearly three decades represented more than 300 men and women statewide who were sexually molested by priests and church officials struck a similar warning tone.

Richard Serbin, who over the years has identified more than 100 predatory priests to law enforcement officials, explained that the math alone - six dioceses, hundreds of priests and multiple decades - signals what is certain to be a stunning report.

In the Altoona-Johnstown Diocese investigation, Serbin, for example, provided information on more than 100 victims who as children had been sexually assaulted by a single pastor.

That pastor - Brother Stephen Baker, a Franciscan friar at the St. Bernardine Monastery near Blair County - had been athletic trainer at Bishop McCort Catholic High School in Johnstown and had worked with hundreds of children. In early 2013, Baker fatally stabbed himself in the monastery, where he had been living.

"You can imagine the number of victims when you have over a hundred child predators," Serbin said. "The numbers can be staggering and I believe are staggering. I think we are likely talking of the thousands."

Many of Serbin's clients were cited in the 2016 grand jury report into the Altoona-Johnstown Diocese.

Serbin applauded Erie Bishop Lawrence Persico for last week releasing a list of 34 priests and 17 lay people who had over the past 70 years been identified in credible accusations of child sexual abuse.

"It's a step in the right way," Serbin said. "What gets lost is the failure to identify child predators and that means that if they are still alive and active there potentially could be future children who are sexually molested. Identifying them, whether they are currently in ministry or diceased, I think is helpful. It shows the scope of the problem."

Tim Lennon, president of the SNAP - or Survivors Network of those Abused by Priests - agreed that lack of transparency on the part of the church, which has historically shielded abusive priests, has further hindered the willingness of victims to come forward.

The lifting of restrictions on information - whether imposed by the church or a grand jury - ultimately helps victims, many of whom never go public with accounts of their abuse.

"It provides really good function of bringing awareness to the community. That's what we want to do make sure the community is aware and vigilant," Lennon said.

Dougherty said he is certain the scope of the upcoming grand jury investigation report will be so severe it could propel Pennsylvania in the direction of Australia, which is poised to prosecute the country's top Catholic official, Cardinal George Pell.

Vatican Cardinal George Pell arrives at the Melbourne Magistrates Court in Melbourne, Australia, in March. A father has testified in an Australian court that his son said he was sexually abused by Pell during a waterskiing outing years ago. A defense lawyer accused the man's son of lying. (Joe Castro/AAP via AP)

The case against Pell stemmed from a national inquiry into child abuse in Australia a few years ago. The Australia Royal Commission into Institutional Responses to Child Sexual Abuse in 2012 launched an investigation into how the Catholic Church and other institutions responded to sexual abuse of children in Australia over 90 years.

Dougherty said he is certain predatory priests remain in the ministry across Pennsylvania.

"I have no doubt," he said. "From my experience this is about power and control. People who have power aren't going to stop. We had laws against what they did and that didn't stop them."

Carolyn Simpson, as spokesperson for the Office of Attorney General, last week cautioned against any characterizations made about the grand jury investigation by people outside the scope of the investigation.

"Protecting the secrecy of Statewide Investigating Grand Juries is paramount," she said. "Only those individuals directly involved with the Grand Jury are aware of its inner workings, and any speculation on current or former investigations from people outside of that small population should be dismissed."

Simpson directed anyone with information related to sexual abuse by members of clergy to call the AG's hotline: 888-538-8541.

Editor's note: This was updated with information on the letter released Monday by the Harrisburg Diocese.