Section 45

Section 45 is the gateway to expert evidence in Indian courts — it makes expert opinions relevant on matters requiring special knowledge. Without Section 45, courts would have to resolve technical questions (forensic pathology, DNA profiling, digital forensics, handwriting examination) without specialised assistance. **The four original categories:** 1. *Foreign law:* When the dispute involves the law of another country — e.g., whether a contract governed by English law was validly formed — an expert on English law is needed. 2. *Science or art:* The broadest category — covers forensic medicine (cause of death), DNA profiling, ballistics, toxicology, psychiatry, engineering, and virtually any specialised scientific or technical field. 3. *Handwriting:* Forensic document examiners — comparing disputed signatures, detecting forgeries, identifying writing instruments. 4. *Finger impressions:* Fingerprint experts comparing latent prints to known exemplars. **Section 45A — Electronic Evidence Examiner (IT Act S.79A):** Added by IT Act amendment, Section 45A creates a specific sub-category of expert for electronic evidence: the Examiner of Electronic Evidence, a person designated under Section 79A of the IT Act by the Central Government. Their opinion on electronic evidence matters is a 'relevant fact.' This is the IEA's recognition that digital forensics requires a specific certification framework. **DNA evidence under Section 45:** The Supreme Court has held that DNA evidence is admissible under Section 45 as 'science' — a DNA scientist is an expert whose opinion the court can consider. However, DNA evidence's weight depends on the laboratory's accreditation, the chain of custody, and the expert's qualifications. The court can accept or reject DNA opinion — it is not conclusive. **Expert opinion is opinion evidence — not conclusive:** Courts are not bound by expert opinion. Section 45 makes expert opinion relevant — the court must consider it, but can disagree with it if other evidence points differently. The court is the ultimate fact-finder; experts assist, not decide. **The BSA Section 39 extension — digital forensics:** BSA Section 39 explicitly adds 'electronic form' and specifically covers opinions on 'matters relating to electronic records, computers, or digital systems.' It also updates the examiner categories to reflect modern forensic practice.