The person in charge of the investigation (case officer) holds no responsibility whatsoever, for ensuring that the law and these principles are adhered to.
An audit trail or other record of all processes applied to computer-based electronic evidence should be created and preserved. An indepedent third party should be able to examine those processes and achieve the same result.
No action taken by law enforcement agencies or their agents should change data held on a computer or storage media, which may subsequently be relied upon in court.
In exceptional circumstances, where a person finds it necessary to access original data held on a computer or storage media, that person is able to do so, regardless of their qualifications or digital forensic knowledge.