The son of Fred Russell, a brilliant ventriloquist on the London variety stage of the teens, Parnell briefly followed in his father's footsteps before turning to theatrical promotion. After mounting several revues like Beauty on Parade in the 1920s and 1930s, he suffered a nervous breakdown in 1934 and was in and out of British bankruptcy courts for the next few years. Following a family dispute, Parnell went to America and distinguished himself as an advertising wonder boy. Returning to England, yet another family fracas forced him away this time to Australia where his tireless efforts as a theatrical producer made him an important figure in that country's entertainment industry. In 1942, Parnell immigrated to America with his sights set upon a theatrical producing career in Hollywood. His one success, The Beaustone Affair, played for a record setting eleven weeks at the Las Palmas Theatre in 1951. Four weeks into the show's run, the press revealed that the play's author, "L. Len Rap," was in fact, Parnell (with his name spelled in reverse). In the mid-1940s, the theatrical producer resuscitated his advertising career and founded a highly profitable direct mail business, Canterbury Press. He was also president of Karseal, Inc., a wax polish firm sharing offices with his advertising business at 915 W. Highland Avenue in Hollywood.
Known by friends and business associated to be prone to spells of moodiness, Parnell also suffered from a dangerous physical condition in which any bruise he sustained could result in a life-threatening blood clot. These maladies combined with the recent tumult in his business life, perhaps, offer an insight into the deadly rampage that was to come. Early in 1954, Parnell became convinced that Beryl Erickson, his executive secretary at Canterbury Press, was responsible for the loss of several big accounts. Despite being close friends with the 35-year-old divorced mother of three young children, Parnell hired a private investigator to monitor Erickson's activities. Concurrent with the investigation, the 59-year-old businessman's house was twice burgled. At Parnell's request, the P.I. purchased his employer a .38-caliber pistol ostensibly for home protection. The situation apparently improved on April 7, 1954 when Parnell sold a controlling interest in Canterbury to Erickson and instructed his operative to destroy all documents pertaining to the investigation. He seemed in a good mood and told everyone he was taking his third wife on a trip to Australia before settling down in his home country of England.
Prior to the opening hours on May 19, 1954, the janitor in the Highland Avenue building housing Canterbury Press and Karseal, Inc. made a gruesome discovery. Beryl Erickson lay face-down on the floor beside her desk dead from a single gunshot wound inflicted at close range to the left side of her face, below the temple. Parnell's briefcase was beside the body and among the documents found in it was a detective magazine with a front page article entitled, "She Was His Woman and He Was Ready to Kill to Keep Her!" The businessman's body was found in a nearby executive washroom where he had shot himself in the right temple. Attempts to explain Parnell's murder of Erickson and his suicide as motivated by any romantic interest between them were discounted by everyone who knew the close friends.