In an interview, however, Mr. Twede said he was not certain that this was the reason he was facing excommunication. He has also written posts on his personal blog, linked to MormonThink, about how he recently started attending church again after five years as an atheist. He described how he had struck up a friendship with a Mormon he called Pat and had e-mailed materials to Pat and Pat’s spouse that he hoped would shake their faith.

Mr. Twede said that last Sunday, after he attended a worship service at his congregational meetinghouse in Orlando for only the second time, he was called into an office and “interrogated” for 45 minutes by the bishop; the stake president, who is a regional church authority; and two councilors, none of whom he had previously met.

“They said that they felt I was a spy and a wolf in sheep’s clothing,” Mr. Twede said. “They said that they need to protect the flock from the Antichrist, from an apostate.”

They handed him a brief letter signed by the stake president, Allan T. Pratt, which said that “because you are reported to have been in apostasy,” they were convening a “disciplinary council” that could excommunicate him. They had spelled his name wrong.

Mr. Twede said that they pressed him for the names of others involved in MormonThink, but that he did not cooperate. He said that there were about 12 occasional writers and 5 steady editors, all volunteers. Mr. Twede said he took over only in July from the managing editor, who quit when he was also faced with excommunication.