We must prove that he "constructively possessed" the gun. There are two kinds of possession - physical and constructive. Physical is when you have the weapon on you and constructive is when you have control over the weapon or the area, but it is not on your person.
Since there were only two adults in the house, we were forced to bring in the other adult to say it was not her gun. So, on Valentine's Day, the girlfriend testified against her boyfriend. How did you spend your Valentine's Day?