A new investigation by the Illinois attorney general's office has identified 500 priests and clergy members with credible claims of sexual abuse against them, all of whom have not been previously identified by church officials and some of whom are still active within the church.

On Wednesday, outgoing Illinois Attorney General Lisa Madigan released the preliminary findings of an investigation that her office launched in August of this year.

Before her office's investigation, the six diocese in Illinois had publicly named 140 priests with claims against them. After Madigan's investigation began, the Catholic Church named an additional 45 priests themselves.

But Madigan's investigation has found 500 separate priests and clergy with credible abuse claims against them, according to Maura Possley, the communications director for the attorney general.

"Because I know that the church has too often ignored survivors of clergy sexual assault, I want to share the initial findings from our work," Madigan said in a statement released along with her preliminary findings on Wednesday.

The Illinois report is the latest update in connection with a string of ongoing investigations into sex abuse within the Catholic church across the country.

The names of the 500 priests and clergy have not been publicly released by Madigan's office and Possley noted that the investigation is ongoing.

Possley confirmed that some of the 500 priests and clergy are active ministry, but did not disclose how many and noted that the investigation into the accusations against them continues.

Of the 185 priests and clergy identified by the Archdiocese of Chicago and the five other diocese in Illinois, each individual is listed as either deceased or liaised, which means they have been removed from the church, except for three individuals in Springfield who were classified as "not active in ministry."

In the statement released by Madigan's office, it notes that Madigan "anticipates additional names will be disclosed as her office’s investigation continues."

"While the findings are preliminary, they demonstrate the need for and importance of continuing this investigation," Madigan said in the statement.

Madigan chose not to seek re-election for a fifth term so she will be leaving office in January, but her successor, Kwame Raoul, posted on Twitter Wednesday that he is "committed to continuing this work when I begin my term as attorney general."

Madigan's report states that the her office "found multiple examples where the Illinois Dioceses failed to notify law enforcement or DCFS [Department of Children and Family Services] of allegations they received related to clergy sexual abuse of minors" and noted that different dioceses used different criteria to determine whether a claim against an individual should be considered credible.

"While the Illinois Dioceses have touted their 'independent audits' as evidence that they are adequately responding to clergy sexual abuse allegations, the audits are seemingly not designed to discover clergy abuse, but rather are perfunctory, 'check the box' exercises done in a routine manner by the same entity nationwide, using a process that does not appear to involve a systematic review of the contents of files or the decisions a diocese made," the report states.

Cardinal Blase Cupich, the archbishop of Chicago, released a statement expressing his "profound regret of the whole church for our failures to address the scourge of clerical sexual abuse."

"There can be no doubt about the constant need to strengthen our culture of healing, protection, and accountability. While the vast majority of abuses took place decades ago, many victim-survivors continue to live with this unimaginable pain," Cupich said in his statement.

The archdiocese noted in the statement that they "stand ready to cooperate with all institutions and agencies that care for children."

There are now at least 16 jurisdictions across the country that have launched investigations into clerical sex abuse following the release of a Pennsylvania grand jury report detailing the alleged cover-up of decades of abuse by hundreds of Catholic priests.

In addition to the ongoing Illinois investigation, officials in Arkansas, Delaware, Florida, Maryland, Michigan, Missouri, Nebraska, New Jersey, New Mexico, New York, Pennsylvania, Vermont, Virginia and the District of Columbia -- as well as the Archdiocese of Anchorage in Alaska -- told ABC News their offices were reviewing their options and considering taking similar action.