100 were wounded and 8 police officers killed.

Following the riot, the authorities quickly moved to detain all of the anarchists and socialist in town. The eight speakers at the (what had been a peaceful) protest meeting were charged with the murder of the police officers.

The police had already, the day before, shot and killed some people at a meeting at McCormick Harvesting Machine Company for no apparent reason.

At the Haymarket Square meeting police moved in to disperse the crowd at the end of the last speech, and someone threw a bomb into the crowd.

This caused the police to start shooting indiscriminately into the crowd and it was this that caused the deaths of the eight police officers, and not the bomb as reported at the time.

7 of the 8 defendants received the death sentence, four of them were hanged on 11 November 1887. One of the men killed himself before his execution. The remaining three were pardoned in 1893 after they had served 7 years in prison.