the facts of the prosecution 's case that andy never contested were these : that he had a wife , linda collins dufresne ; that in june of 1947 she had expressed an interest in learning the game of golf at the falmouth hills country club ; that she did indeed take lessons for four months ; that her instructor was the falmouth hills golf pro , glenn quentin ; that in late august of 1947 andy learned that quentin and his wife had become lovers ; that andy and linda dufresne argued bitterly on the afternoon of 10 september 1947 ; that the subject of their argument was her infidelity .