Warren Knox Billings (July 4, 1893 – September 4, 1972) was a labor leader and political activist, who was convicted with Thomas Mooney of the San Francisco Preparedness Day Bombing of 1916.

Billings served 23 years in prison before being released in 1939 and finally being pardoned in 1961 by governor Edmund G. Brown.

This is when he was approached by a man outside the employment office who showed him a red card of the Industrial Workers of the World (IWW).

Billings was convicted and imprisoned for one year on a charge of possession of dynamite for the Pacific Gas & Electric strike in 1913.

[3] His association with Mooney, who was a well known socialist and militant, strengthened the prosecution’s connection between Billings and the Preparedness Day bombing, which took place on July 22, 1916 in San Francisco.

[5] The bombing took place during the height of anarchist violence in the United States by the Galleanist anarcho-communist movement of Luigi Galleani.

Billings was arrested along with Thomas Mooney and his wife Rena and a driver named Israel Weinberg.

The trials of both Warren and Mooney were being followed extensively and it is alleged that the witnesses were coached by detective Swanson and by the prosecutors, D.A.

There was world wide outrage and US President Woodrow Wilson got involved and asked California Governor William Stephens to step in and reduce their sentence to life imprisonment, or at least stay the impending execution.