Whether substantial evidence supported the jury's finding that Perez murdered Mesa willfully, deliberately, and with premeditation.
Holding
Yes. The circumstantial evidence reasonably supported an inference that Perez reflected and decided to kill Mesa, rather than acting only on an unconsidered or rash impulse.
Reasoning
Appellate review asks whether, viewing the whole record in the light most favorable to the judgment, substantial evidence would permit a rational jury to find premeditation and deliberation beyond a reasonable doubt. The reviewing court does not choose among competing reasonable inferences or substitute its factual judgment for the jury's merely because the evidence might also support a contrary conclusion.
Premeditation means consideration beforehand, and deliberation means a decision reached through careful thought and weighing of considerations. The relevant inquiry is the extent of reflection, not the amount of time involved; a cold and calculated decision can form quickly.
The Court explained that People v. Anderson supplies useful categories of evidence—planning activity, motive, and manner of killing—but does not create mandatory elements or a rigid checklist. The Anderson factors are descriptive aids to appellate review, not an exclusive formula that must be met in every first degree murder case.
The jury could infer planning from Perez's conduct. It could conclude that he entered the house surreptitiously while Mesa's car was warming up, did not park in her driveway, and armed himself with a steak knife obtained from the kitchen. These circumstances supported an inference that his conduct was purposeful rather than wholly spontaneous.
The jury could also infer a motive to silence Mesa as a witness. Perez and Mesa knew each other from high school, so she could identify him. Whatever prompted the entry or initial assault, the jury could reasonably find that Perez decided to kill her once he recognized that she could identify him.
The manner of the attack further supported deliberation. After the first knife broke and cut Perez, evidence of blood in the kitchen knife drawer allowed the jury to infer that he searched for another knife and used it to continue the attack. Obtaining and using another weapon, like reloading a gun, provided a basis to find a reasoned decision to ensure Mesa's death rather than a single uncontrolled outburst.
The post-assault evidence reinforced that inference. Perez did not simply flee; the evidence showed that he searched drawers and jewelry boxes and tended his bleeding hand. Although these acts alone would not prove premeditation, the jury could view them with the weapon evidence and the manner of killing as inconsistent with an entirely rash and impulsive homicide.
The Court distinguished People v. Anderson, where a brutal attack with numerous wounds was insufficient without evidence linking the killing to reflection. This record was stronger because it permitted inferences of weapon acquisition, witness-elimination motive, and a renewed decision to kill after the first knife broke. The evidence was not overwhelming, but it was sufficient under the deferential substantial-evidence standard.