Erich Koch, a 72-year-old white male of German descent, died on May 6, 1933, in Cincinnati, Ohio. His death was one of the earliest known murders attributed to Anna Marie Hahn, a German-born woman who became one of America's most notorious female serial killers during the early 20th century. Koch had immigrated to the United States and was living in Cincinnati at the time of his death. He became acquainted with Hahn, who often presented herself as a caregiver or companion to elderly German men, many of whom were isolated or had no close family nearby.
At the time of his death, Koch appeared to have died of natural causes, and there was no immediate suspicion of foul play. However, it later emerged that Anna Marie Hahn had ingratiated herself with Koch under the pretense of care and assistance. Notably, shortly before his death, Koch transferred ownership of his house to Hahn, a move that, in hindsight, was clearly orchestrated as part of her pattern of exploiting vulnerable elderly men for financial gain.
Years later, as suspicions mounted around a string of similar deaths involving elderly men with connections to Hahn, authorities began to re-examine Koch's case. The turning point came in 1937 when multiple bodies were exhumed during the investigation into Hahn's activities. Forensic analysis revealed that Koch, like the other victims, had died from arsenic poisoning. These findings confirmed that his death had been anything but natural—it was a calculated, premeditated murder designed to enrich Hahn.
Anna Marie Hahn was arrested in 1937 and charged with multiple counts of murder, including that of Erich Koch. Her trial received significant media attention due to both the shocking nature of her crimes and the rare occurrence of a female serial killer. She was found guilty and became the first woman to be executed in Ohio's electric chair in 1938.
Koch's case played a pivotal role in uncovering the full extent of Hahn's crimes. His status as one of her earliest known victims provided investigators with key patterns in her modus operandi—targeting elderly, often German-American men; establishing trust; manipulating legal documents; and ultimately poisoning them with arsenic. The death of Erich Koch thus marked the beginning of a murderous spree that would claim at least five confirmed lives before Hahn's arrest ended her deadly schemes.
