Alfred Andrew Knapp (1863 – August 19, 1904), known as The Hamilton Strangler, was a 19th-century American serial killer responsible for killing at least five women and girls between 1894 and 1902.

[4] On December 21, 1902, Hannah Knapp (née Goddard), Alfred's third wife, suddenly disappeared from her Cincinnati home.

[4] After her disappearance, Alfred spent several days in Cincinnati, constantly visiting his sister Sadie Wenzel, before suddenly announcing that he was looking for his missing wife.

[1][5] Knapp's trial was considered a great sensation by the contemporary press and public, transforming him into a sort of "celebrity".

[6][3] The prosecution had little to no evidence, as during the first trial there were no clues tying him to the murder of his wife, adding to the fact that her body still hadn't been found yet.

Despite the verdict severely affecting his sister and mother, Knapp appeared disinterested in the ordeal, as he was quoted three hours after the trial as saying: "I suppose it is all off with me.

[10] On July 22, an appeal was filed on Knapp's behalf by his lawyer, Thomas Darby, to the State Board of Pardons.

On August 19, 1904, Alfred Knapp was executed by electric chair in the Ohio Penitentiary, dying six minutes after the initial shock.