The declaration to the police set off four raids in which the authorities seized hundreds of case files from the commission’s current leader, detained a group of bishops for more than nine hours and disturbed the tomb of a cardinal where construction work had recently been done. Investigators drilled into the tomb and lowered a camera, but found only the remains.
Investigators are now analyzing more than two truckloads of seized documents, many related to 475 complaints lodged with the sex-abuse commission after the resignation in April of a popular bishop who admitted that, early in his career, he had molested a boy.
The former head of the commission, Godelieve Halsberghe, said in an interview with a Flemish newspaper, Het Nieuwsblad, that she had gone to the authorities after receiving a call from a man who did not identify himself and warned her in French to “watch out” for herself and to secure the documents she held on about 30 cases she had handled during her tenure at the commission, from 2000 to 2008.
Ms. Halsberghe, now a retired magistrate, has long been critical of the church’s efforts in Belgium to confront its past. Alarmed by the phone call, she took the documents in her keeping to the authorities and warned them that the church might be hiding others. On Monday, she declined to accept calls.
The Belgian prosecutor’s office — the object of Vatican fury over the raids — confirmed that there had been a formal accusation but declined to discuss the source. “We are working on a specific case about a specific declaration,” said a spokesman, said Jean-Marc Meilleur. “We are not starting an inquisition against the church.”
Ms. Halsberghe’s case records, she told the newspaper, included documents from victims and records of conversations with Cardinal Godfried Danneels, who retired in January and whose home was among the targets of the Belgian raids last week.
Over the next few weeks, investigators will be comparing records from the church and the commission to evaluate whether some cases had remained secret, they said.
Church officials said they remained mystified by the police action and continued to denounce the disruption of the tomb and question its purpose. Eric de Beukelaer, a spokesman for the leader of the Belgium church, said: “When we were told, we could hardly believe it. Maybe they have a good reason for doing that, but we are here guessing.”
Ms. Halsberghe’s successor at the church commission, Peter Adriaenssens, resigned Monday along with other members, complaining that the Belgian authorities had let their group collect information as the complaints flooded in after the resignation of Bishop Roger Vangheluwe, and pounced as the flow began to dwindle.
“We were bait,” Mr. Adriaenssens told reporters on Monday, before being questioned by investigators.
Prosecutors are considering whether to expand beyond gathering evidence against abusers to encompass those who knew children were in peril but failed to protect them. “You have a part of a case that could be against the ones who committed the crimes and you also could have another part of the case against those who didn’t help someone who was in danger,” Mr. Meilleur said.
On Tuesday, the Vatican will honor the head of the Belgian church, Archbishop André-Joseph Léonard, who was one of the clerics held and questioned last week at the ornate palace of the archbishop of Mechelen-Brussels. The archbishop will be one of 30 church officials to receive the pallium, a vestment worn by the pope that is conferred as a mark of association with the papacy and its powers.