EoH: Ah, the imaginary "secret cache".
So, if we imagine a person has been shot in the street. The victim has several gunshot wounds in their body; there is gunshot residue on their clothing; there are empty shell casings on the ground; a witness saw it happen. Unfortunately the gunman ran off, taking the shotgun with him. In your world then no crime was committed because we do not have the primary piece of evidence - the weapon. And in your world all the secondary circumstantial evidence accounts for nothing.