On this day in 1886, close to midnight, Captain Michael Hennessey, Chief of the Houston Detective Agency, is shot and killed as he stepped off a streetcar in Houston Texas.

A couple of days later a man named H.D. Melton was arrested for the murder. A witness placed him at the scene a few minutes prior to the shooting and that combined with the fact that Melton’s wife hated Hennessey due to him sending a relative of hers to prison placed suspicion on the man.

At trial on October 6 the judge dismissed the case due to a lack of evidence. Hennessey grew up in New Orleans and, along with his more famous cousin David Hennessey, was involved in two well publicized and famous cases there in 1881.

In July of that year he and David captured a fugitive from Sicilian justice and well known bandit Giuseppe Esposito in the French Quarter’s Jackson Square. Esposito was also most likely an important man in the Crescent City’s Mafia affairs. A few months later in October in an incident stemming from the Esposito capture, the cousins were involved in a shootout on a New Orleans street with another law officer in which Michael was severely wounded. (See Shootout on Gravier Street in the Crescent Corner).

As with the murder of David Hennessey several years later there was much speculation if Micheal’s murder was some long awaited revenge by Mafia elements for the Esposito capture or from friends of the man killed in the shootout with the cousins.

On the night of 30th September 1886, Captain Michael Hennessey, Chief of the Houston Detective Agency, stepped off a streetcar in Houston, Texas, and into the darkness of a waiting assassin. Close to midnight, shots rang out and Hennessey fell mortally wounded, bringing a violent end to the career of one of the more colourful lawmen of the era and leaving behind a mystery that would never be fully resolved.

Within days of the killing, a man named H.D. Melton was taken into custody. A witness placed him near the scene just minutes before the shooting, and investigators quickly noted a compelling personal motive — Melton's wife harboured a deep grudge against Hennessey, blaming him for sending a relative of hers to prison. The circumstantial case, however, proved insufficient to convict. When the matter came before a judge on 6th October, the charges were dismissed for lack of evidence, and the true identity of Hennessey's killer slipped permanently beyond the reach of justice.

To understand the full weight of that September night, one must look back to New Orleans, where Michael Hennessey had made his name alongside his cousin, the more celebrated lawman David Hennessey. In July 1881, the two men pulled off a remarkable feat, tracking down and capturing Giuseppe Esposito in the French Quarter's Jackson Square. Esposito was a notorious Sicilian bandit and fugitive, wanted in his homeland and widely believed to be a significant figure in New Orleans' emerging Mafia network. The arrest sent shockwaves through the city's criminal underworld and brought the Hennessey cousins squarely into the crosshairs of some very dangerous men.

The fallout came swiftly. Just months later in October 1881, in an incident directly linked to the Esposito affair, the cousins found themselves in a violent street confrontation on Gravier Street with a fellow law officer. Michael was severely wounded in the exchange, a bullet finding him before the smoke had cleared. He recovered, but the incident underscored just how perilous the terrain the Hennesseys were navigating truly was.

When Michael was gunned down five years later in Houston, speculation naturally turned toward the same shadowy forces. Had the Mafia's long memory finally caught up with him? Were loyalists of Esposito, or friends of the man slain on Gravier Street, settling old scores? No definitive answer ever emerged, though the parallels with David Hennessey's own notorious assassination in New Orleans in 1890 only deepened the suspicion. The fate of the Hennessey cousins remains one of the more haunting chapters in the early history of organised crime in America.