Racial tensions, police suspicion and the Panthers' radical politics had already proved a volatile combination. Founded in 1966, the party quickly became a menacing, yet romanticized, force. In the two years before the raid, police and Panthers had engaged in eight gun battles nationally, in which three police officers and five Panthers died. Four of the shootouts, including one in which two police officers were killed, occurred in Chicago.

The party’s original purpose was to patrol African American neighbourhoods to protect residents from acts of police brutality.