In July 2018, Sandi Nichols of
Indianapolis, Indiana, while going through her recently deceased mother's personal effects, discovered a "Dying Declaration Letter" written by her grandfather, W. Glenn Martin, some 70 years before (October 26, 1949). The handwritten envelope read, "In case of Margaret Ellen's or Glenna Jean's Death" and was initialed "WGM"; the letter was written out of fear that one or both of his teenage daughters might be killed. The three-page letter identified W. Glenn Martin as a paid LAPD police informant working for a "Sgt. McCawley" (Sgt. McCauley, LAPD Internal Affairs Division). He described his activities as working undercover for LAPD detectives to help them identify and arrest corrupt police officers; in his words, "... it was to try and see if other officers could be inveigled into crime." The Martin letter, reproduced in full in the chapter "Afterword" in
Black Dahlia Avenger III,
[8] went on to name "GH" on 17 separate occasions identifying him as a personal acquaintance of Martin's as well as of Sgt. McCauley's, and named him as the killer of both Elizabeth "Black Dahlia" Short and of a second lone woman, Louise Springer, the "Green Twig Murder" victim. Martin's letter claimed that both he and "GH" personally knew the Springer woman and that he believed "GH" also killed her. LAPD at that time was actively investigating the Louise Springer and Black Dahlia murders and had publicly identified them as "probably connected". Springer was
garroted on June 13, 1949, just two blocks from where the body of Elizabeth Short was found in 1947.
Included in the letter was the fact that LAPD, after being informed that "GH" knew victim Springer, that "GH" was taken in and "grilled about the Springer murder". The Martin letter made it clear that "GH" was known and protected by law enforcement officers, and that they "let him go". Martin's instructions were that his letter was to be opened only in case of harm coming to either of his daughters. No harm came to either of them so the letter remained unreported and in the family's possession for 70 years until discovered and read by Martin's granddaughter.