Herman Petrillo was born in Italy in the late 19th century, likely during the 1880s, and emigrated to the United States in 1910, settling in Philadelphia, Pennsylvania. At the time, the Italian-American community in the city was rapidly expanding, doubling from roughly 76,000 in 1910 to over 155,000 by 1930. Herman arrived with his cousin, Paul Petrillo, and together they became embedded in the city's underworld.

Herman had a reputation for being both streetwise and ruthlessly opportunistic. He was a skilled counterfeiter and arsonist, deeply connected to the criminal underbelly of South Philadelphia. By the early 1930s, he had built a network of fellow immigrants, thugs, insurance agents, and occult practitioners, all used to facilitate an increasingly deadly insurance scam enterprise.

While Paul operated under the guise of a small tailor shop, Herman stayed behind the scenes as the planner and executor. His talents in fraud and violence complemented Paul’s charisma and manipulation of the community’s superstitious beliefs. Herman gained infamy among insiders for his cold euphemism, “send them to California,” a coded phrase that meant someone was marked for death.

Herman had multiple brushes with the law before the murder charges: insurance fraud, arson, and suspected counterfeiting. But his ability to evade prosecution emboldened him, allowing him to operate unchecked for several years. By the time authorities finally connected the dots, at least a dozen Italian-American men had been murdered under suspiciously identical circumstances.

The Philadelphia Poison Ring began its operations in 1931, masterminded by Herman Petrillo and supported by his cousin Paul. Their plan was chilling in its simplicity and effectiveness. Herman would arrange for a victim, often an Italian immigrant man, to be secretly insured with policies that included double indemnity clauses for accidental death. Then, working with local thugs or superstitious women (often the victim’s spouse), Herman would orchestrate the murder to look like an accident.

The first known victim was Ralph Caruso, killed in 1931 during a staged fishing trip where he was drowned and bludgeoned. A similar fate awaited Joseph Arena, murdered the following year. John Woloshyn, another victim, was first bludgeoned and then run over by a car to simulate a traffic accident. These staged accidents, combined with fraudulent insurance policies, provided a profitable stream of payouts for the ring.

As the Great Depression worsened, Herman’s operations expanded. Together with Paul, he recruited Morris Bolber, a Russian-Jewish immigrant and self-proclaimed psychic, along with a group of “fattuchierie” or wise women: Maria Carina Favato, Josephine Sedita, and Rose Carina. These women, familiar with folk magic, sold potions and spells to desperate women hoping to escape loveless or abusive marriages. Many of these potions were laced with arsenic or antimony, slowly poisoning their unsuspecting husbands.

Herman's scam relied heavily on cheap life insurance policies. At the time, policies under $500 required no medical exam and could be taken out without the knowledge or signature of the person being insured. In some cases, victims unknowingly signed insurance papers marked with an "X", or their signatures were forged altogether.

The ring unraveled after the death of Ferdinando Alfonsi in October 1938. Alfonsi had been unknowingly insured and began suffering violent symptoms consistent with heavy metal poisoning. His wife, Stella Alfonsi, had been recruited by the ring and was under the influence of one of Herman’s so-called “love potions.” An undercover informant named George Meyer, alongside agents Landvoight and Phillips, had been working to catch Herman in the act. Their sting operation confirmed that Herman had tried to contract Meyer to murder Alfonsi by hitting him with a car. However, Alfonsi had already been fatally poisoned before the plan could be executed.

When Alfonsi died, an autopsy revealed extremely high levels of arsenic in his system. That death became the key that blew the case wide open. Investigators soon linked a pattern of arsenic-related deaths to individuals with suspicious insurance policies, all tracing back to either Herman or Paul Petrillo.

Herman Petrillo was arrested in late 1938 and convicted of first-degree murder in 1940. Despite appeals, he was executed by electric chair at Rockview Penitentiary on January 22, 1941, alongside his cousin Paul. In total, the poison ring was connected to at least 17 suspicious deaths, though the true number may be higher.