A person answering the phone at the religious affairs bureau of Hebei Province, where Bishop Shi oversaw Catholics in a rural county, would not give his name and said he had no idea whether the bishop had died, only that he had “disappeared for many years.”

Another official with the bureau’s Catholic Office said over the phone that he had only “heard of Bishop Shi” but did not know anything else. “In recent years, it’s impossible for us to just arrest a person based on his Catholic belief,” he added, refusing to give his name. “If a person is imprisoned, he must have broken some laws.”

Ms. Cheung said Bishop Shi’s family had heard rumors as long as three years ago that he had died. “They are quite prepared to receive the news, but they at least want to get the remains back,” she said.

The family could not be reached for comment.

Despite the continued detentions of the bishops, the boundary between the official Chinese church and the Vatican has blurred significantly in recent years.

“You can be a perfectly good loyal Catholic, loyal to the Vatican and in the official church,” said Henrietta Harrison, a professor of modern Chinese history at Oxford University who studies Catholicism in China. “The Catholic Church is a global institution. They’re all part of it.”

Yet deep tensions remain over the appointment of bishops. Those tensions burst into the open in July 2012, when Thaddeus Ma Daqin, who had just been appointed bishop of Shanghai, announced at his consecration that he was resigning from the official church, the Chinese Patriotic Catholic Association. He was then stripped of his title and spent 20 months in a seminary outside of Shanghai and was required to take Communist indoctrination classes, Reuters reported last year.

The other bishop still in detention is Su Zhimin, who is from Baoding. He has been detained without charge since 1997.