Law question... help?

I have to do a mock trial at school and I have been given the role of Prosecutor. The case is about two police officers who have come to the scene of a one-car accident to help keep traffic moving along and stabilize the situation. One of the police officers gets into the car to move it out of the road because the car owner is injured; but notices that there is a flat tire. He gets out of the car and goes into the trunk to get a spare tire and finds weed (7.5 ounces) and money (500 dollars in twenties). I need to somehow prove that this search was reasonable. Is there anywhere in the Criminal Code that covers this or does anyone know of a precedent?