If it happens again...
... take pictures.
Most of us have camera phones. Take pictures of the scene; sun angle; sight lines; witnesses; pretty much anything that could be a factor.
Record any statements made, if possible.
(This is for a traffic accident.)
One instructor advises that, if possible, it is better to have a witness take photos of any SD shooting scene. If the shooter takes pictures, it could strike witnesses or prosecutors as trophy-taking behavior, rather than legal CYA.