In the Lake of the Moon. Stuart Haydon Series, #4

The first photograph arrived at Stuart Haydon's house on Monday, in an unmarked manila envelope. It was a black-and-white photograph of an oil painting, the painting, the portrait of a young man. Something about him was disturbingly familiar. It was not until Tuesday, when the next envelope arrived, that Haydon recognized-this time from a photograph taken fifty years earlier-the youthful features of his own father.
Wednesday and Thursday brought two more envelopes, and startling photographs of an exotically beautiful young woman. Haydon knew that Friday's photograph would be the most explicit of the serries, but he was unprepared for what he saw. It "hit him like a physical blow to his stomach, and he almost gasped, a convulsive wave of nausea rising from deep within him .