11 Cal. App. 4th 1276, 15 Cal. Rptr. 2d 473 (Cal. Ct. App. 1992)
People v. Acosta is a staple case in criminal law courses for its treatment of proximate cause in homicide, especially where intervening acts by third parties contribute to the fatal result.
In a homicide prosecution arising from a high-speed police pursuit, does a fleeing driver proximately cause the deaths of officers when two pursuing police helicopters collide, or does the midair collision constitute a superseding cause that breaks the chain of criminal causation?
A defendant is criminally liable for homicide if his conduct is a substantial factor in bringing about the victim's death and the result is not so highly unusual or extraordinary in retrospect as to be outside the scope of the risk created. Intervening acts by third parties, including the negligent or mistaken responses of law enforcement or rescuers, do not relieve the defendant of liability unless they are independent, unforeseeable, and so abnormal as to constitute a superseding cause. California courts often articulate this in terms drawn from tort law and the Restatement (Second) of Torts, including the highly extraordinary in retrospect standard. Separately, second-degree implied malice murder requires proof that the defendant acted with a conscious disregard for human life, meaning a subjective awareness that his conduct endangers life and a deliberate decision to act despite that knowledge.
The helicopter collision was not, as a matter of law, a superseding cause that broke the chain of causation; there was sufficient evidence from which a jury could find that Acosta's reckless flight was a proximate cause of the deaths because the involvement of police air support and the risk of collision were not highly extraordinary in retrospect. However, the court concluded that the evidence was insufficient to establish implied malice for second-degree murder as to the helicopter occupants and reversed the second-degree murder convictions, remanding for further proceedings consistent with its opinion.
Acosta is a leading California case aligning criminal proximate cause analysis with tort principles. It reinforces that the negligent responses of law enforcement or rescuers are ordinarily foreseeable and do not, without being highly extraordinary, sever the causal chain. For students, the case highlights the separate roles of causation and mens rea: a defendant can proximately cause a death without necessarily possessing the malice needed for murder. The decision offers a durable framework for exam analysis where unusual intervening events occur during pursuits, rescues, or medical treatment following a defendant's dangerous act.