The Cincinatti, Ohio, suburb of Cumminsville was the location of a mysterious string of brutal slayings that date back to the early years of the twentieth century. Despite the best efforts of investigators at the time there are still no answers in this baffling case and it is unlikely that there ever will be. Like his contemporary, Jack The Ripper, Cumminsville's "mad killer" will probably never be identified.

The terror began on May 4, 1904, when 31-year-old Mary McDonald was found near death close to some railroad tracks. Initially it was believed that she must have been hit by a train earlier that morning (one of her legs was severed) and she had simply been the victim of a tragic accident. It was later determined by detectives that McDonald had been savagely beaten on the head and then likely pushed onto the tracks in an effort to cover up the crime. She succumbed to her injuries later that day.

On October 1 a second victim was claimed by the Cumminsville serial slayer. Louise Mueller, 21, was found bludgeoned to death near some tracks. On November 2 the killer struck again, beating 18-year-old Alma Steinigewig to death and leaving her corpse dumped like rubbish in a vacant lot.

After a six year hiatus the murders began again. Anna Lloyd, 43, was killed on New Year's Eve of 1909. She had been beaten savagely on the head and her throat cut. The next October brought the final homicide in the series. On the 25th of the month 26-year-old Mary Hackney was found slain in her home, her throat slashed and skull fractured. With Hackney the killings ended, but not the mystery of the "mad killer" of Cumminsville.

Despite a massive search for the killer, police never seemed to have come upon a solid suspect. However, private detectives claimed in 1913 that they knew who had slain Anna Lloyd. The man was a former streetcar conductor who had since been locked up in a sanitarium. No charges were ever filed against this nameless suspect, however, and no link between him and the other four victims seems to exist.

A series of letters mailed to authorities by somebody dubbing himself "S.D.M." and claiming to be involved in the Cumminsville murders was ultimately believed to be nothing more than a sick hoax.