Little Blues Book, Brian Robertson, page 43, paragraph 1

Johnson's death is attributed to poisoning. The reason for the killing? Johnson's habit of picking out a woman in the audience—single or married—and bit by bit directing each song in her direction, working his slow seduction. It’s said that on one particular night, Jonson’s magic worked so well that a woman’s husband—the bartender—retaliated by giving the bluesman a bottle of whiskey laced with poison.

Algonquin, 1996, Chapel Hill, 1-56512-137-6