Chain of custody only covers from when the evidence came into the hands of the police; the real issue here is original provenance, which chain of custody doesn't solve.
Evidence of provenance is already important, to be sure, but the the ability to have some degree of validation of the contents has itself provided some evidence of provenance; lose that and there is a real challenge.
Evidence of provenance is already important, to be sure, but the the ability to have some degree of validation of the contents has itself provided some evidence of provenance; lose that and there is a real challenge.