Gilbert Vasquez went to his friend Abel Rivera’s house. While there, Vasquez got into an argument with Abel’s brothers Timotheo (defendant) and Gilbert, who then attacked Vasquez. Timotheo stabbed Vasquez six times, Gilbert shot Vasquez three times, and Vasquez died from his wounds. The brothers were charged separately. During Timotheo’s trial for murder, the trail court instructed the jury that Timotheo was guilty if he either killed Vasquez himself, or acted as a party with Gilbert to kill him. Timotheo was convicted and sentenced to life imprisonment. He appealed, alleging that the evidence was insufficient to prove beyond a reasonable doubt that he had murdered Vasquez.