The group, the Survivors Network of those Abused by Priests, known as SNAP, is neither a plaintiff nor a defendant in the litigation. But the group has been subpoenaed five times in recent months in Kansas City and St. Louis, and its national director, David Clohessy, was questioned by a battery of lawyers for more than six hours this year. A judge in Kansas City ruled that the network must comply because it “almost certainly” had information relevant to the case.

The network and its allies say the legal action is part of a campaign by the church to cripple an organization that has been the most visible defender of victims, and a relentless adversary, for more than two decades. “If there is one group that the higher-ups, the bishops, would like to see silenced,” said Marci A. Hamilton, a law professor at Yeshiva University and an advocate for victims of clergy sex crimes, “it definitely would be SNAP. And that’s what they’re going after. They’re trying to find a way to silence SNAP.”

Lawyers for the church and priests say they cannot comment because of a judge’s order. But William Donohue, president of the Catholic League for Religious and Civil Rights, a church advocacy group in New York, said targeting the network was justified because “SNAP is a menace to the Catholic Church.”