Get with the program. If you want to revise your definition, be my guest. Then, you need to explain why you stated just the opposite in your original statement. I agree that this is a nonsensical argument. Perhaps you can do better on the next attempt.
Legal evidence is the most common form of indirect evidence.
For example - a dead body with one bullet lodged in the head, a smoking gun with one bullet missing, and a suicide note laying on the floor is indirect evidence of an act of suicide. The actual event of the self-murder was unobserved and could have been set up to look like a suicide when in fact it was a homicide. You have, yourself, shown that the evidence in your sample case could have been staged. As such, the clear possibility exists for multiple reasonable explanations even though one may be clearly more possible than any other. The important consideration here is no explanation in this sample case is without objective evidence to support it and that sufficient evidence must be available in order to construct a positive case in favor of any given solution to the crime before any court can accept it.