On the night of November 13, FBI Special Agent Mitchell met with informant William O’Neal and showed him photos of the two dead police officers killed earlier that day by Spurgeon Winters. In a series of meetings in the following days, Mitchell had O’Neal help map out the exact layout of Fred Hampton’s apartment, including the specific location of his bed and nightstand. He also asked O’Neal to keep tabs on who was coming and going from the apartment and to determine what weapons were kept there.

Armed with this information, a raiding party of fourteen SPU officers arrived outside Hampton’s apartment at 4:30 A.M. on December 4. They did not bring the standard raiding equipment they had used in previous Chicago Panther raids, such as tear gas or sound equipment; instead, they carried a Thompson submachine gun, five shotguns, a carbine, nineteen .38 caliber pistols, and one .357 caliber pistol. The assault was quick and decisive. Within fifteen minutes, Fred Hampton was dead, shot twice through the head while he lay in bed. Peoria, Illinois, Panther leader Mark Clark, in Chicago attending a statewide meeting of Party leaders, was also dead. The seven other Panthers in the apartment—four with bullet wounds—were arrested on charges of attempted murder, aggravated battery, and unlawful use of weapons. One SPU officer was shot in the leg.