The Haymarket affair (also known as the Haymarket massacre or Haymarket riot) was a demonstration and unrest that took place on Tuesday May 4, 1886, at the Haymarket Square in Chicago. It began as a rally in support of striking workers. An unknown person threw a dynamite bomb at police as they dispersed the public meeting. The bomb blast and ensuing gunfire resulted in the deaths of eight police officers, mostly from friendly fire, and an unknown number of civilians. In the internationally publicized legal proceedings that followed, eight anarchists were tried for murder. Four men were convicted and executed, and one committed suicide in prison, although the prosecution conceded none of the defendants had thrown the bomb.
The Haymarket affair is generally considered significant for the origin of international May Day observances for workers. In popular literature, this event inspired the caricature of "a bomb-throwing anarchist." The causes of the incident are still controversial. The deeply polarized attitudes separating business and working class people in late 19th-century Chicago are generally acknowledged as having precipitated the tragedy and its aftermath. The site of the incident was designated a Chicago Landmark on March 25, 1992. The Haymarket Martyrs' Monument in nearby Forest Park was listed on the National Register of Historic Places and designated a National Historic Landmark on February 18, 1997...
Trial, executions and pardons
Eight people connected directly or indirectly with the rally and its anarchist organizers were arrested afterward and charged with Degan's murder: August Spies, Albert Parsons, Adolph Fischer, George Engel, Louis Lingg, Michael Schwab, Samuel Fielden and Oscar Neebe. Five (Spies, Fischer, Engel, Lingg and Schwab) were German immigrants and a sixth, Neebe, was a U.S. citizen of German descent. The other men, Parsons and Fielden, were born in the U.S. and England, respectively. Two other individuals, William Seliger and Rudolph Schnaubelt, were indicted, but never brought to trial. Seliger turned state's evidence and testified for the prosecution, and Schnaubelt fled the country before he could be brought to trial.
Louis Lingg (September 9, 1864 – November 10, 1887) was a German anarchist who committed suicide while in jail, after being arrested as an agitator during the Haymarket Square bombing...
Lingg became an apprentice carpenter from 1869 to 1882. He then took a job in Strasbourg, in Alsace, then moved on to Fribourg, Germany where he joined the Working Men's Educational Society, a socialist organization...
In July 1885, Lingg arrived in New York City then departed for Chicago where he joined the International Carpenters and Joiners' Union...
On May 4, 1886, Lingg was not present at Haymarket Square for what would be known as the Haymarket Riot. A bomb was thrown into the crowd of policemen by an unidentified person. Seven men were arrested the next day with no evidence in connection with the bombing. Lingg himself was discovered in his hiding place on May 14 and fought with the police officer before being finally subdued by his landlord...
There was no evidence that any of the men arrested had participated in the bombing, but they were all charged on June 21 with criminal conspiracy, on the theory that their anarchistic writings incited the bomber. Lingg and six others were convicted and sentenced to death. Oscar Neebe was sentenced to fifteen years in prison. Lingg commented when he heard of the court's decision, "I die happy on the gallows, so confident am I that the hundreds and thousands to whom I have spoken will remember my words. When you shall have hanged us, then they WILL do the bombthrowing! In this hope do I say to you: I despise you, I despise your order, your laws, your force propped authority. Hang me for it."
On November 6, 1887, four bombs were discovered in Lingg's cell, causing fear of an escape or attack on Chicago by the defendants and causing serious harm to the defendants' public opinion and support.
Lingg, the youngest of those sentenced to death, took his own life four days later, on November 10, the day before he was scheduled to hang.  He used a small bomb (a blasting cap smuggled to him by a fellow prisoner). He put it in his mouth and lit it at 9AM; it blew off his lower jaw and destroyed a large portion of his face. He survived in agony for another 6 hours, until his death at around 3PM. It was believed by many that he didn't want his fate to be in the hands of the oppressors and would rather be a martyr for the cause, by his own volition.
Lingg was buried, in a plot marked since 1893 by the Haymarket Martyrs Monument, in the Waldheim Cemetery (now Forest Home Cemetery) in Forest Park, Chicago.
Who threw the bomb?
While admitting none of the defendants was involved in the bombing, the prosecution made a weak argument that Lingg had built the bomb and two prosecution witnesses (Harry Gilmer and Malvern Thompson) tried to imply the bomb thrower was helped by Spies, Fischer and Schwab. The defendants claimed they had no knowledge of the bomber at all.
Several activists, including Dyer Lum, Voltairine de Cleyre and Robert Reitzel, later hinted they knew who the bomber was. Writers and other commentators have speculated about many possible suspects:
... An agent provocateur was suggested by some members of the anarchist movement. Albert Parsons believed the bomber was a member of the police or the Pinkertons trying to undermine the labor movement. However, this contradicts the statements of several activists who said the bomber was one of their own. Lucy Parsons and Johann Most rejected this notion. Dyer Lum said it was "puerile" to ascribe "the Haymarket bomb to a Pinkerton."