Which of the following is NOT necessary for an arson conviction?

For an arson conviction, it is essential to establish certain elements. One of these crucial elements is proof of a fire, as arson specifically involves the intent to set fire to property. Another important factor is the evident intention to commit the crime, which demonstrates that the individual had a clear purpose behind their actions.

While having a witness to the act can support the case and contribute to the evidence against the accused, it's not a strict requirement for conviction. Similarly, while motive can help explain why someone might commit arson, it is not a necessary element that needs to be established in court for a conviction to occur. This means that motives such as financial gain or revenge, while potentially relevant, are not essential to proving that a crime of arson has taken place.

Therefore, the absence of a motive does not negate the possibility of convicting someone of arson, making it the correct answer to the question of what is NOT necessary for an arson conviction.