In the story " The Case of the Defaced Painting" by , it is clear that Mrs. Williams is guilty of ruining the Wyeth painting because she is married but was not wearing her wedding ring, and she was biting her nails on the same hand - suggesting that she may got rid of the evidence of blue paint.
Mrs. Williams was motivated to ruin the painting because she was angry that her husband was treating her family poorly. She decided that she needed to ruin something he loved too, his painting.
