Forensic reports often arrive in court clothed with an aura of
science, certainty and neutrality, particularly in cases involving DNA,
fingerprints, ballistics, toxicology and digital forensics. Yet appellate
courts have repeatedly reminded that such reports are only as reliable as the
process by which samples are collected, preserved, transmitted, tested and
interpreted. If any link in this process is weak, the probative value of the
entire forensic edifice may collapse.
This article sets out a practical framework for trial judges,
public prosecutors and defence counsel to scrutinise forensic evidence across
six critical stages:
(1) chain of custody,
(2) contamination and preservation,
(3) scientific methodology,
(4) expert’s qualifications and neutrality,
(5) documentation and procedural trail and
