The Wall Street bombing occurred at 12:01 pm on September 16, 1920, in the Financial District of Manhattan, New York City. The blast killed 30 people immediately, and another eight died later of wounds sustained in the blast. There were 143 seriously injured, and the total number of injured was in the hundreds.:160–61
The bombing was never solved, although investigators and historians believe the Wall Street bombing was carried out by Galleanists (Italian anarchists), a group responsible for a series of bombings the previous year. The attack was related to postwar social unrest, labor struggles, and anti-capitalist agitation in the United States.
The Wall Street bomb killed more people than the 1910 bombing of the Los Angeles Times, which was the deadliest act of terrorism on U.S. soil up to that point. The death toll was exceeded in the Bath School disaster in 1927.
At noon, a horse-drawn wagon passed by lunchtime crowds on Wall Street and stopped across the street from the headquarters of the J.P. Morgan bank at 23 Wall Street, on the Financial District's busiest corner. Inside the wagon, 100 pounds (45 kg) of dynamite with 500 pounds (230 kg) of heavy, cast-iron sash weights exploded in a timer-set detonation,:77 sending the weights tearing through the air. The horse and wagon were blasted into small fragments, but the driver was believed to have left the vehicle and escaped.
The 38 fatalities, most of whom died within moments of the blast, were mostly young people who worked as messengers, stenographers, clerks, and brokers. Many of the wounded suffered severe injuries.:329–30 The bomb caused more than $2 million in property damage ($23.9 million today) and destroyed most of the interior spaces of the Morgan building.
Within one minute of the explosion, William H. Remick, president of the New York Stock Exchange, suspended trading in order to prevent a panic. Outside, rescuers worked feverishly to transport the wounded to the hospital. James Saul, a 17-year-old messenger, commandeered a parked car and transported 30 injured people to an area hospital. Police officers rushed to the scene, performed first aid, and commandeered all nearby automobiles as emergency transport vehicles.
The Justice Department's Bureau of Investigation (BOI, the forerunner of the Federal Bureau of Investigation) did not immediately conclude that the bomb was an act of terrorism. Investigators were puzzled by the number of innocent people killed and the lack of a specific target, other than buildings that suffered relatively superficial, non-structural damage. Exploring the possibility of an accident, police contacted businesses that sold and transported explosives. By 3:30 pm, the board of governors of the New York Stock Exchange had met and decided to open for business the next day. Crews cleaned up the area overnight to allow for normal business operations the next day, but in doing so they destroyed physical evidence that might have helped police investigators solve the crime.:160–61 The New York assistant district attorney noted that the timing, location, and method of delivery all pointed to Wall Street and J.P. Morgan as the targets of the bomb, suggesting in turn that it was planted by radical opponents of capitalism, such as Bolsheviks, anarchists, communists, or militant socialists.:150–51
Investigators soon focused on radical groups opposed to U.S. financial and governmental institutions and known to use bombs as a means of violent reprisal. They observed that the Wall Street bomb was packed with heavy sash weights designed to act as shrapnel, then detonated on the street in order to increase casualties among financial workers and institutions during the busy lunch hour. Officials eventually blamed anarchists and communists. The Washington Post called the bombing an "act of war." The Sons of the American Revolution had previously scheduled a patriotic rally for the day after (September 17) to celebrate Constitution Day at exactly the same intersection. On September 17, thousands of people attended the Constitution Day rally in defiance of the previous day's attack.:166–68
The bombing stimulated renewed efforts by police and federal investigators to track the activities and movements of foreign radicals. Public demands to track down the perpetrators led to an expanded role for the U.S. Justice Department's Bureau of Investigation, including the General Intelligence Division of the BOI headed by J. Edgar Hoover.:272–82 The New York City Police Department also pushed to form a "special, or secret, police" to monitor "radical elements" in New York City.
On September 17, the BOI released the contents of flyers found in a post office box in the Wall Street area just before the explosion. Printed in red ink on white paper, they said: "Remember, we will not tolerate any longer. Free the political prisoners, or it will be sure death for all of you." At the bottom was: "American Anarchist Fighters.":171–75 The BOI quickly decided that the flyer eliminated the possibility of an accidental explosion. William J. Flynn, Director of the BOI, suggested the flyers were similar to those found at the June 1919 anarchist bombings.:171–75
The investigation conducted by the Bureau of Investigation stalled when none of the victims turned out to be the driver of the wagon. Though the horse was newly shod, investigators could not locate the stable responsible for the work.:171–75 When the blacksmith was located in October, he could offer the police little information.:225–26
Robert W. Wood helped to reconstruct the bomb mechanism.
Investigators questioned tennis champion Edwin Fischer, who had sent warning post cards to friends, telling them to leave the area before September 16. He told police he had received the information "through the air." However, they found Fischer made a regular habit of issuing such warnings, and had him committed to Amityville Asylum, where he was diagnosed as insane but harmless.
The Bureau of Investigation and local police investigated the case for over three years without success. Occasional arrests garnered headlines but each time they failed to support indictments.:217–19, 249–53 Most of the initial investigation focused on anarchists and communists, such as the Galleanist group, whom authorities believed were involved in the 1919 bombings.:207–08 During President Warren G. Harding's administration, officials evaluated the Soviets as possible masterminds of the Wall Street bombing:261–90 and then the Communist Party USA.:295–308 In 1944, the Federal Bureau of Investigation, successor to the BOI, investigated again. It concluded that its agents had explored many radical groups, "such as the Union of Russian Workers, the I.W.W., Communist, etc....and from the result of the investigations to date it would appear that none of the aforementioned organizations had any hand in the matter and that the explosion was the work of either Italian anarchists or Italian terrorists.":325
One Galleanist in particular, Italian Anarchist Mario Buda (1884–1963), an associate of Sacco and Vanzetti, and the owner of a car which led to the arrest of the latter for a separate robbery and murder, is alleged by some historians, including Paul Avrich, to be the man most likely to have planted the bomb. Avrich and other historians theorize that Buda acted in revenge for the arrest and indictment of his fellow Galleanists, Sacco and Vanzetti. Buda's involvement as the Wall Street bombmaker was confirmed by statements made by his nephew Frank Maffi and fellow anarchist Charles Poggi, who interviewed Buda in Savignano, Italy, in 1955. Buda (at that time known by the alias of Mike Boda) had eluded authorities at the time of the arrests of Sacco and Vanzetti, was experienced in the use of dynamite and other explosives, was known to use sash weights as shrapnel in his time bombs, and is believed to have constructed several of the largest package bombs for the Galleanists:15 (Buda was also a suspect in the Preparedness Day Bombing of San Francisco July 22, 1916). These included a large black powder bomb that killed nine policemen in Milwaukee, Wisconsin in 1917. Buda was in New York City at the time of the bombing, but he was neither arrested nor questioned by police.
After leaving New York, Buda resumed the use of his real name in order to secure a passport from the Italian vice-consul, then promptly sailed for Naples. By November he was back in his native Italy, never to return to the United States. Other Galleanists still in the U.S. continued the bombing and assassination campaign for another twelve years, culminating in a 1932 bomb attack targeting Webster Thayer, the presiding judge in the Sacco and Vanzetti trial. Thayer, who survived the ensuing blast that destroyed his house and injured his wife and housekeeper, moved his residence to his club for the remainder of his life, where he was guarded 24 hours a day.
The bombing has inspired several books, including The Death Instinct, by Jed Rubenfeld and Buda's Wagon: A Brief History of the Car Bomb (2007) by Mike Davis.
The bombing is referenced in Clive Cussler's 2014 book Bootlegger.