Chief David Hennessy was assassinated by members of the New Orleans mob. He was on his way home from a police department board meeting when he was ambushed and killed. It is believed he was killed to prevent testimony in a trial later in the week.
A total of nine men were charged with his murder. Six of the men were acquitted and three others were cleared in mistrials. All nine suspects and two other men were lynched by angry citizens after the trials.
Chief Hennessy had served with the agency for 20 years. He had originally been hired as a messenger boy and worked his way up to chief of police. He was survived by his mother. He is buried in Metairie Cemetery, New Orleans, Louisiana.