Mr. Spofford has denied the allegations of sexual misconduct and has said he had nothing to do with the vandalism. (The man in the blue raincoat, who was caught on video, is not him.) Last year, he accused New Hampshire Public Radio, which has about two dozen journalists, of trying to pin the attacks on him “to try to deter me from bringing legal action, because they know I will win.” Mr. Spofford soon sued NHPR and Ms. Chooljian, among others, for libel.

Ms. Chooljian and her colleagues do not know who was behind the vandalism, but they are convinced that it was connected to their investigation into Mr. Spofford.

“That’s being a journalist in America today,” Ms. Chooljian said in an interview.

Mr. Spofford said in a statement that The New York Times was spreading the same “false accusations” that NHPR had aired. “We should all be concerned when media outlets team up in an unfair character assassination,” he said.

This week, New Hampshire Public Radio is releasing a podcast, “The 13th Step,” about its investigation into Mr. Spofford and the broader recovery industry, as well as the threats the news organization has faced along the way.

On the advice of NHPR’s security consultants, Ms. Chooljian and her family will be hunkering down out of state.