Interesting legal theory you have there, but in fact, a crime is a crime as soon as it is committed. Is it your assertion that a murder is not a crime until the murderer has been charged and prosecuted?
Have you ever heard of manslaughter? Justifiable homicide? The various degrees of homicide? Self-defense? Sometimes what looks like murder turns out to be suicide. Just because someone has died under suspicious circumstances doesn’t automatically make it murder until there is a law enforcement investigation and a criminal complaint is issued, usually through an indictment by a grand jury.
Here in America, all alleged defendants are entitled to the have the burden of proof in criminal allegations fall to the government. It is a constitutional principle that requires the government to prove the guilt of a criminal defendant and relieves the defendant of any burden to prove his or her innocence.
Barack Obama doesn’t have to prove that his birth certificate isn’t forged, the government (city, county, state or federal) must prove beyond a reasonable doubt that it is forged. The first step in that process is to conduct a formal law enforcement (or congressional) investigation.