Cavitt (defendant) and Williams (co-defendant) made and executed a plan with Cavitt’s girlfriend (Mianta) to rob the home of Mianta’s 58-year-old stepmother, Betty. On December 1, 1995, Cavitt and Williams entered the home with Mianta’s help and, as planned, covered Betty with a sheet, tied her up and stole guns, jewelry, and other valuable items from the home. They left her face-down on the bed, tied up and beaten. In an effort to make Mianta look like a victim, Cavitt and Williams left her at the house tied up as well. Mianta eventually untied herself and called her father to inform him of the crime, but at that point Betty had already died of asphyxiation. Cavitt and Williams were charged with felony murder under § 189 of the California Penal Code. At trial, the defense offered evidence to support its theory that Mianta intentionally killed her stepmother after Cavitt and Williams completed their escape out of a personal vendetta, and therefore the felony murder rule did not apply. The trial court denied a defense request for a jury instruction to the effect that felony murder requires that the killing be “in furtherance of” the underlying felony. Cavitt and Williams were convicted in separate trials of felony murder. The Court of Appeal affirmed their convictions. Cavitt and Williams appealed to the Supreme Court of California.