On This Day In Herstory. On January 5, 1953 Ethel Milne Gumm Gilmore was found dead in the parking lot of Douglas Aircraft, where she worked in Santa Monica, California. Ethel succombed to a heart attack, she was 59. Judy was in New York when she heard the news about her mother's death and flew out to California that very day and made arrangements for Ethel's funeral.