Robert George Irwin was born on August 5, 1907, in Arroyo Seco Park, Pasadena, California. He was the son of evangelist parents, with his father, Rev. Benjamin Hardin Irwin, being a prominent figure in the Holiness movement. Irwin's early life was marked by instability; his father deserted the family before Robert was three years old, leading to a childhood of poverty and hardship. Irwin spent time in a state reformatory, where he discovered a talent for sculpting. 

He later studied under renowned sculptor Lorado Taft and worked for a waxworks studio in Los Angeles, creating busts of public figures, including President Herbert Hoover. Despite his artistic promise, Irwin struggled with mental health issues, leading to multiple hospitalizations. He became infatuated with Ethel Gedeon, a woman he met while boarding at her family's home, but his feelings were unreciprocated. This unrequited love, combined with his deteriorating mental state, set the stage for the tragic events that would follow.

On Easter Sunday, March 28, 1937, Robert George Irwin committed a triple homicide in the Beekman Hill area of New York City's Turtle Bay neighborhood. His victims were Mary Gedeon, her daughter Veronica Gedeon, and a boarder named Frank Byrnes. Irwin had previously boarded with the Gedeon family and had developed an obsession with Ethel Gedeon, who no longer lived at the residence. Upon finding Ethel absent, Irwin strangled Mary Gedeon and her daughter Veronica, and stabbed Frank Byrnes to death. 

The murders garnered significant media attention, partly due to Veronica's work as a model, which led to the publication of numerous photographs in the press. Irwin fled the scene, initiating a manhunt that spanned multiple states. He was eventually apprehended in Chicago after surrendering to a newspaper in exchange for payment. Irwin confessed to the murders, citing his obsession with Ethel and his mental instability as factors. He was indicted on three counts of first-degree murder but ultimately pleaded guilty to second-degree murder to avoid the death penalty. Irwin was sentenced to 139 years to life and spent the remainder of his life in mental institutions, dying in 1975.