Mr. Singleton, the executive director of the Greater Astoria Historical Society, started an offshoot called Friends of Steinway Mansion in 2011, when the mansion went on the market for the first time in nearly 90 years. Mr. Singleton did not raise the money to buy the place, but that did not stop him from pressing for it to become “a spark to revitalize the area,” perhaps as an arts center. Or maybe a community center. Or a museum.

In September, he excitedly called supporters, saying that someone with deep pockets had contacted him and outlined a plan to buy the mansion and set up the music school. Mr. Singleton, corresponding with the person by email, sought and received a promise that the person would attend the historical society’s already scheduled meeting on Sept. 21 and talk about what he had in mind.

The person was a no-show, but by then, Mr. Singleton was not surprised. A few days before the meeting, the Gmail account that the man had been using was terminated and his Facebook page disappeared.

“Pretty elaborate setup to be a simple hoax,” Mr. Singleton said then.

He insists now that he was suspicious all along.

“The first thing I did as soon as he said, ‘I bought the mansion, I want to start this music school,’ I thought, ‘Bang, I’ve got something here, go to the press, let’s vet this in the press,’ ” Mr. Singleton said last week. “I thought: ‘You guys vet this. You see what it’s all about.’ ”