While on duty Officer O'Brien engaged in a confrontation with four drunken men on Marshall Street between Hancock and Clay Streets. One of the men, Frank Kleber, pulled a pistol and fatally shot Officer O'Brien in the abdomen. Officer O'Brien managed to return fire and hit Kleber twice.

Kleber survived the shooting. He and one of the other four men were charged in the officer's death. Frank Kleber was charged with murder but in a trial was found guilty of a lesser crime. He was sentenced to three years in the penitentiary. An accessory to murder charge against the other individual was dismissed.

Officer O'Brien served with the Louisville Division of Police from 1895 until his death.

Sources:
- Information obtained from the Courier-Journal newspapers: November 4, 5, & 12, 1897 and May 12, 1898.
- "Louisville Division of Police, 1806-2002" by Retd LPD Capt Mort Childress.

While on duty Officer O'Brien engaged in a confrontation with four drunken men on Marshall Street between Hancock and Clay Streets. One of the men, Frank Kleber, pulled a pistol and fatally shot Officer O'Brien in the abdomen. Officer O'Brien managed to return fire and hit Kleber twice.

Kleber survived the shooting. He and one of the other four men were charged in the officer's death. Frank Kleber was charged with murder but in a trial was found guilty of a lesser crime. He was sentenced to three years in the penitentiary. An accessory to murder charge against the other individual was dismissed.

Officer O'Brien served with the Louisville Division of Police from 1895 until his death.

Sources:
- Information obtained from the Courier-Journal newspapers: November 4, 5, & 12, 1897 and May 12, 1898.
- "Louisville Division of Police, 1806-2002" by Retd LPD Capt Mort Childress.