CHICAGO, Illinois — Three men and one woman who say they were sexually abused by priests decades ago filed a lawsuit Thursday against every diocese in Illinois for an alleged ongoing scheme to cover up sexual assault by priests.

The lawsuit was filed in Chicago by attorney Jeff Anderson, who has represented clergy abuse victims across the country, and seeks to compel dioceses throughout Illinois to provide the names of all their priests accused of child molestation.

“Defendants have, for decades, continued to adopt policies and practices of covering up criminal activity…(that) have endangered numerous children in the past and these practices will continue to put children at risk in the future,” reads the lawsuit against all six dioceses in Illinois, as well as the Catholic Conference of Illinois.

While the lawsuit does seek damages and only claims instances of abuse against children in three dioceses — Rockford, Peoria and Springfield — all of them have been and continue to cover up clergy sexual abuse, Anderson said.

He added that a key goal of the suit is to force each diocese to make public the names of all priests, living and dead, accused of child molestation. He pointed to a similar lawsuit filed in Minnesota that eventually forced the Archdiocese of St. Paul to add dozens of names to the list of credibly accused priests.

Anderson also filed a similar lawsuit in California earlier this month.

The lawsuit contends that while some dioceses have turned over information about certain priests accused of sexually molesting children, others refuse to make the names public. The Belleville and Rockford dioceses, the suit said, have not named a combined 53 priests accused of child molestation since 1950.

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“All of them have covered up and continue to cover up, are guilty of withholding their files and we are seeking to force the bishops to come clean, to require that all of them disclose fully the names of all the offenders they know who have violated children… in their diocese,” Anderson said.

The Archdiocese of Chicago said in a statement that while officials had not reviewed the lawsuit, the diocese has in recent years taken significant steps to address the issue, including posting the names of priests who have been credibly accused of child sexual abuse on its website.

The Chicago diocese has implemented a “stringent monitoring program of clergy with substantiated cases of sexual abuse against them,” the statement said.

The Diocese of Joliet disputed any suggestion that it’s withholding information. In a statement, the diocese said that since 2006 it has kept on its website a list of “living and deceased diocesan priests who have been credibly accused of child sexual abuse.”

In Peoria, the diocese in a statement defended its handling of allegations against two priests named in the lawsuit. In one case, the diocese said that upon learning of the allegations it immediately placed the priest on leave and reported the allegation to police. Only after the police concluded its investigation, and the Diocesan Review commission found the allegation unsubstantiated, was the priest reinstated in ministry.

The other priest, according to the Peoria diocese, was removed from all public ministry in 2002.

Other dioceses did not immediately return calls for comment.

The specific allegations against five priests across Illinois cited in the lawsuit, three of whom are still alive and in the priesthood, contain similar details.

Darin Buckman, one of the three named plaintiffs, said in the suit that when he was an altar boy at a Peoria church starting around 1979, a priest sexually abused him at a time when his “inappropriate conduct with children was known” to the diocese.