During a criminal investigation, the prosecutor submitted the original hard drive from the suspect's computer as evidence. The defense objected during the trial proceedings, and the evidence was…

Chain of custody documentation records every person who handled the evidence, timestamps, and transfer reasons, establishing an unbroken record that proves the evidence was not substituted or tampered with between seizure and trial - courts routinely reject evidence lacking this documentation.

Creating a bit-for-bit forensic image with cryptographic hash verification and sealing the original drive as evidence preserves the integrity of the source media; performing all analysis on the verified copy ensures the original remains unaltered, removing any basis for a defense challenge that the investigation modified the evidence.

Running forensics software directly on the original hard drive risks altering file system metadata, access timestamps, or slack space, which can invalidate the evidence and provides grounds for a defense to argue the data was modified.

A tape backup does not create a sector-by-sector identical image, may skip system areas and unallocated space, and lacks cryptographic hash verification needed to prove the copy is forensically identical to the original.

Creating a forensic image alone is necessary but insufficient without also maintaining chain of custody documentation - both practices together are required for evidence to be admissible in court.