The binding legal principles established are: (1) A copy of a document is inadmissible as secondary evidence to prove the contents of the original unless it is proved that the original has been lost, destroyed, or cannot be produced for an acceptable reason (following R v Amod & Co (Pty) Ltd 1947 (3) SA 32 (A)). (2) An admission made by an accused in cross-examination as to the source or authenticity of a document can render that document admissible even if the accused's knowledge is secondhand, provided the admission is clear and unequivocal; the weight to be attached to such evidence depends on all relevant proven facts (following S v Naidoo 1985 (2) SA 32 (N) and Sher v Administrator, Transvaal 1990 (4) SA 545 (A)). (3) In theft cases involving stolen motor vehicles, proof of guilty knowledge (mens rea) may be established through circumstantial evidence showing conduct consistent only with knowledge that the vehicle was stolen, including: concealment of the vehicle's origins, fraudulent registration, use of false identification numbers, and implausible explanations for possession. (4) It is impermissible for an accused's evidence-in-chief to consist of counsel reading a prepared statement into the record, as this amounts to an improper leading of evidence that deprives the court of the ability to assess the accused's testimony properly. (5) Misdirections by a trial court in admitting inadmissible evidence do not necessarily vitiate a conviction if the remaining admissible evidence, properly considered, proves guilt beyond reasonable doubt.