Francisco Salas (defendant) robbed a bar. Police officers gave chase to Salas's getaway car and stopped Salas a few minutes later, only 1.2 miles from the bar. When a police officer approached Salas's car, Salas fatally shot him and then fled on foot, but police soon apprehended him. The State of California (plaintiff) prosecuted Salas for felony murder. At issue was whether, for purposes of the felony-murder rule, Salas shot the officer while "in the perpetration of" armed robbery. Salas claimed he did not intend to kill the officer. The leading case, People v. Boss, 210 Cal. 245 (1930), held that the perpetration of robbery continues, no matter how far from the scene of the robbery or how long afterward, so long as the robber (1) is being pursued and has not reached a place of temporary safety and (2) has no more than a "scrambling possession" of his plunder. The trial judge instructed the jury on pursuit but refused Salas's request to define scrambling possession for the jury. The jury convicted Salas and the judge sentenced him to death. On appeal to the Supreme Court of California, Salas argued that the judge failed to properly instruct the jury on scrambling possession, and that the prosecution failed to prove that Salas had no more than scrambling possession of his plunder.