A person is not liable as an accomplice (socius criminis) to murder merely by being present at the scene of the crime, even with knowledge that a crime is being committed, unless the state proves that the accused had prior knowledge of the planned crime and aided, abetted, or participated in its execution. Common purpose must be established to hold multiple accused equally liable for murder. Actual intent to kill (dolus directus) can be inferred from the choice of weapon, the manner of attack, the nature and severity of injuries inflicted, and the circumstances surrounding a premeditated revenge killing. An alibi defence will be rejected where the accused's testimony is inconsistent, confused, and contradicted by independent evidence, and where the alibi witness fails to materialize despite opportunities provided.