Authored By: Mpho Mkhonto
University of South Africa
Abstract
This Article explores how forensic evidence contributes to criminal convictions in South Africa by evaluating its legal foundations, evidentiary strengths, and practical limitations. Using a doctrinal research methodology, the study analyses constitutional provisions, statutory frameworks, case law and leading academic commentary to assess how courts admit, interpret, and weigh scientific findings such as DNA profiles and expert testimony. While forensic techniques can significantly enhance the accuracy of criminal adjudication, their effectiveness is influenced by persistent challenges, including laboratory delays, uneven technical capacity and potential weaknesses in expert reasoning. The article argues that forensic evidence improves the integrity of the justice system when accompanied by robust safeguards, consistent quality-control practices and vigilant judicial oversight.
Introduction:
The Growing Role of Forensics in Criminal Justice Forensic evidence has become an indispensable tool in modern justice systems, transforming investigative processes and strengthening the evidentiary foundations of criminal prosecutions. Its scientific precision and ability to establish causal links between suspects, victims, and crime scenes have positioned forensic science at the centre of truth-seeking mechanisms.1In South Africa, where a high level of violent and organised crime places pressure on the justice system, forensic tools such as DNA profiling, ballistics, fingerprint comparison, and forensic data analysis increasingly play an important role in securing reliable convictions.2 However, despite its potential, the use of forensic evidence raises important questions concerning accuracy, procedural safeguards, constitutional rights, and systematic capacity. Based on the NAS Report, which stated that amongst the above-mentioned forensic evidence, only DNA evidence has proven to establish an accurate causal link between the evidence in question and the individual.3 This is because DNA is unique to each individual and provides compelling evidence, notwithstanding that our judiciary has yet to interpret the scientific principles of DNA profiling with understanding, as the legal fraternity still perceives DNA evidence as infallible, leading to shortcomings in interpretation and admissibility.4 Therefore, to determine whether forensic evidence is accurately interpreted, the credibility of an expert witness is essential for the judiciary to comprehend and evaluate scientific evidence accurately.5Integrity, honesty, and transparency, such as acknowledging and correcting errors, strengthen the reliability of expert testimony.6 Although experts are compensated, their opinions must remain unbiased and rooted solely in objective scientific analysis. Ensuring competence, mitigating cognitive errors, and enhancing the value of expert evidence in court. Through clear communication, adequate preparation, and adherence to professional standards, expert witnesses assist the court in making informed, accurate, and just decisions, aiding the court in reaching a concise record of the processes leading to a sound judgment.7 This article critically analyses the role of forensic evidence in South Africa, examining its strengths and weaknesses, legal framework, case law development, and prospects for reform.
Legal Framework Governing Forensic Evidence in South Africa
Adhering to pertinent legal frameworks is essential to ensuring proper procedures in the utilisation and validation of forensic evidence within the judicial system. Therefore, the use of forensic evidence in criminal proceedings is guided by statutory provisions, constitutional principles, procedural safeguards, and judicial interpretation. It is essential to gain a clear understanding of the above frameworks to ensure the reliability and fairness of forensic evidence in securing convictions.
- The Constitution of the Republic of South Africa, 1996
The Constitution has established guidelines in relation to the handling of forensic evidence, with specifically two rights which play a vital role in this context:
Section 35: Protects and lays out the rights of arrested, detained, and accused persons before the law, especially concerning the adjudication of evidence which could determine the weight of the case brought before the court. In this instance, the reliability of forensic evidence is to be challenged8, and evidence obtained in violation of the Bill of Rights is to be excluded.9 This is crucial when forensic procedures may be flawed or improperly conducted, to guarantee the right to a fair trial.
Section 14 protects the right to privacy to ensure that no intrusive forensic procedures are compelled upon a person, such as the collection of bodily samples, as such procedures must align with constitutional limitations and be authorised by law.10
- The Criminal Procedure Act 51 of 1977 (CPA)
The CPA regulates the acquisition of bodily samples and forensic evidence, outlining critical conditions governing their lawful handling.
Sections 36 and 37 of the CPA allow for the allocation of fingerprints, photographs, and bodily samples, including blood and buccal swabs.11 to be taken by the police12 With or without consent, if the procedure is lawful, conducted by authorised persons, and on reasonable grounds, if they believe that the person in question committed an offence in Schedule 113 Or 8, or the prints taken will be of value to the investigation.14
Section 121 allows expert evidence to be admitted by affidavit or certificate without the expert having to testify, provided that a material fact meets the statutory requirements, and it mainly applies to DNA and ballistic reports.15 These reports are prima facie proof of the facts contained in them.
- The Criminal Law (Forensic Procedure) Amendment Act 37 of 2013 (DNA Act)
This legislation broadens the landscape around South Africa’s forensic laws by establishing the National Forensic DNA Database (NFDD), which provides for clear procedures for the collection, storage, and use of DNA samples.16 This allows police to access DNA samples of arrestees and convicted offenders to help enhance investigative efficiency.17 The act aims to create uniformity and reliability, but it faces physical challenges, which concern backlogs that continue to undermine these objectives.
Strengths of Forensic Evidence in Securing Convictions
Forensic evidence has greatly contributed to the authoritative forms of proof in modern criminal justice systems. It not only provides scientific grounding but also establishes objective, corroborative, and sometimes conclusive links between an accused person, a victim, and a crime scene.18 Recent scholarly works have properly obtained and analysed DNA evidence as one of the most reliable investigative tools available to the criminal justice system, providing strong inferences capable of linking suspects to crime scenes with high statistical accuracy whilst offering corroboration where eyewitness testimony may be weak, contaminated, or unreliable.19 It particularly works in cases of weakened comparative traditional evidence, such as witness testimony, given the fallibility of human memory and the dangers of mistaken identity, thereby furthering the value of forensic science in strengthening the accuracy of convictions.20 Moreover, the establishment and expansion of the National Forensic DNA Database of South Africa (NFDD) has enhanced the probative value of DNA profiling, allowing investigators to generate investigative leads, identify serial offenders, and distinguish between suspects with greater precision.21
Expert evidence also contributes to the principles governing admissibility and reliability, and hasthe duty to assist the court rather than advocate for a party. South African law expects expert testimony to align with its truth-seeking function as a requirement of a fair trial under section 34 of the Constitution.22 The Law of Evidence Amendment Act reinforces this by setting conditions for the admission of opinion evidence, ensuring that expert input is both relevant and necessary to assist the trier of fact.23 Case Law has further refined these principles: In Michael v Linksfield Park Clinic, the court highlighted the importance of evaluating competing expert opinions by assessing their factual foundations, internal coherence, and alignment with established scientific methods.24 Whereas in Schreuder v Viljoen, the Supreme Court of Appeal emphasised that expert conclusions must be anchored in logical reasoning and demonstrate methodological soundness.25 This has led academic authorities to support this position, with Zeffertt and Paizes underscoring the necessity of objectivity and the expert’s overriding duty to the court, in contrast to Schwikkard and Van Der Merwe, who stress that expert credibility rests on independence, sound methodology, and honesty.26 Together, these sources establish that expert witnesses must demonstrate integrity, methodological rigour, and impartiality to ensure that their evidence meaningfully assists the judicial process.
Challenges in Using Forensic Evidence in Criminal Proceedings Despite its value, it is important to understand and conceptualise that the use of forensic evidence in South African courts raises several challenges. Questions often arise about the quality and integrity of forensic processes, including contamination, administrative backlogs, and inconsistent laboratory standards, all of which compromise the evidential weight of scientific findings.27 Courts must also contend with the problem of over-reliance on expert testimony, where scientific conclusions are accepted without adequate scrutiny of the methodology, a concern highlighted by both case law and academic commentary.28 Furthermore, disparities in access to forensic resources between urban and rural policing environments create inequalities in investigative capacity, potentially influencing trial fairness.29 These challenges necessitate stricter adherence to evidentiary material, stronger quality-control mechanisms, and ongoing judicial vigilance when evaluating forensic conclusions.
Recommendations and Reforms
Several key suggestions include:
- Strengthening laboratory capacity and reducing backlogs
- Standardising national forensic protocols
- Enhancing expert witness training and accreditation
- Strengthening the oversight and accountability mechanisms
- Encouraging interdisciplinary collaboration
Implementing these reforms would enhance the credibility and effectiveness of forensic evidence in South Africa’s criminal justice system. To reach the goal of executing just convictions grounded in scientific accuracy, constitutional compliance, and procedural fairness.
Conclusion
Forensic evidence plays a crucial role in enhancing the reliability of convictions in South Africa, particularly through DNA profiling and expert testimony. Its effectiveness, however, depends on adherence to constitutional safeguards and statutory frameworks, such as the Criminal Law (Forensic Procedures) Amendment Act, which govern the collection, analysis, and retention of forensic evidence. Challenges such as laboratory backlogs, methodological errors, and over-reliance on expert opinion highlight the need for judicial scrutiny and rigorous quality-control measures. When properly managed, forensic evidence strengthens both the accuracy of criminal adjudication and the protection of fundamental rights.
Bibliography
Cases
Michael and Another v Linksfield Park Clinic (Pty) Ltd and Another 2001 (3) SA 1188 (SCA) Schreuder v Viljoen 2015 (5) SA 106 (SCA)
Statutes and statutory instruments
The Constitution of the Republic of South Africa, 1996
Criminal Law (Forensic Procedures) Amendment Act 37 of 2013
Criminal Procedure Act 52 of 1977
Law of Evidence Amendment Act 45 of 1988
Books
Schwikkard PJ and van de Merwe SE, Principles of Evidence (4th edn, Juta 2016) Zeffert DT and Paizes AP, The South African Law of Evidence (3rd edn, LexisNexis 2017)
Journal Articles
De Wet S, Oosthuizen H and Visser J, ‘DNA Profiling and the Law of South Africa’ (2011) 14 PER 171
Du Pokoy C, ‘Reasoning the Admissibility of Expert Forensic Evidence in South African Criminal Proceedings’ (2025) 28 PER 1
Knoetze I and Crouse L, ‘DNA Processing Contemplated in the Criminal Law (Forensic Procedure Amendment Act 37 of 2013 and the Constitutional Right to Privacy’ (2016) 37 OBITER 36
Meintjes-van der Walt L, ‘Judicial Understanding of the Reliability of Eyewitness Evidence: A Tale of Two Cases’ (2016) 19 PER 1
Meintjes-van der Walt and Dhliwayo P, ‘DNA Evidence as the Basis for Conviction’(2021) 24 PER 1
Minnaar A, ‘The Impact of Limited Forensic Capacity on Criminal Justice Outcomes in South Africa’ (2019) 136 SALJ 115
Olckers A and Hammatt Z. ‘Science Serving Justice: Opportunities for Enhancing Integrity in Forensic Science in Africa’ (2021) 6 Forensic Science Research 295
Smith JH, Horne JS, de Wet GJ, Singh M, Zeye MM and Simon K, ‘Forensic DNA Expert Evidence in the South African Context’ (2025) 17 African Journal of Legal Studies 137 Tapela C, ‘The State of Forensic Serving in South Africa’ (2019) 136 SALJ 115
1 Lirieka Meintjes-van der Walt, ‘Judicial Understanding of the Reliability of Eyewitness Evidence: A Tale of Two Cases’ (2016) 19 PER 1, 2-4.
2Joe H Smith, Juanida S Horne, Greg J de Wet, Mogambal Singh, Moutanou MJ Zeye and Kate Simon, ‘Forensic DNA Expert Evidence in the South African Context’ (2025) 17 African Journal of Legal Studies 137, 200-205.
3 Chevaure Du Pokoy, ‘Reconsidering the Admissibility of Expert Forensic Evidence in South African Criminal Proceedings’ (2025) 28 PER 1, 2.
4 S De Wet, H Oosthuizen and J Visser, ‘DNA Profiling and the Law in South Africa’ (2011) 14 PEP/PELJ 171, 171-172.
5 Antonel Olckers and Zoe Hammatt, ‘Science Serving Justice: Opportunities for Enhancing Integrity in Forensic Science in Africa’ (2021)
6 Forensic Science Research 295, 299.
6 Olckers and Hammatt, ‘Science Serving Justice: Opportunities for Enhancing Integrity in Forensic Science in Africa’ 299.
7 Olckers and Hammatt, ‘Science Serving Justice: Opportunities for Enhancing Integrity in Forensic Science in Africa’ 299.
8 The Constitution of the Republic of South Africa, 1996, section 35(3)(i).
9 Section 35(5).
10 Section 14.
11 The Criminal Procedure Act 52 of 1977, section 36C, D and E.
12 CPA, s37(1)(a)(i) – s37(1)(b).
13 CPA, s36C(1)(a)(b).
14 CPA, s36D(1)(i) and 36E(2)(a).
15 CPA, s212(4).
16 Izette Knoetze and Lilla Crouse, ‘DNA Processing Contemplated in the Criminal Law (Forensic Procedures) Amendment Act 37 of 2013 and the Constitutional Right to Privacy’ (2016) 37 OBITER 36, 36 – 38.
17 Knoetze and Crouse, ’DNA Processing Contemplated in the Criminal Law (Forensic Procedures) Amendment Act 37 of 2013 and the Constitutional Right to Privacy’ 41.
18 Lirieka Meintjes-Van der Walt and Priviledge Dhliwayo, ‘DNA Evidence as the Basis for Conviction’ (2021) 24 PER 1, 2 and 9.
19 Meintjes-van der Walt and Dhliwayo, ‘DNA Evidence as the Basis for Conviction’ 6 and 9-15.
20 Meintjes-van der Walt, ‘Judicial Understanding of the Reliability of Eyewitness Evidence’ 20.
21 Knoetze and Crouse, ’DNA Processing Contemplated in the Criminal Law (Forensic Procedures) Amendment Act 37 of 2013 and the Constitutional Right to Privacy’ 56.
22 The Constitution, s 34.
23 Law of Evidence Amendment Act 45 of 1988, s 3.
24 Michael and Another v Linksfield Park Clinic (Pty) Ltd and Another 2001 (3) SA 1188 (SCA) par 34-40.
25 Schreuder v Viljoen 2015 (5) SA 106 (SCA) par 26-30.
26 PJ Schwikkard and SE van der Merwe, Principles of Evidence (4th edn, Juta 2016) 335-345.
27 Chiedza Tapela, ‘The State of Forensic Services in South Africa’ (2019) 136 SALJ 115, 118-121.
28 Michael and Another v Linksfield Park Clinic (Pty) Ltd and Another par 36-40; Schwikkard and van der Merwe, Principles of Evidence 325-345.
29 Anthony Minnaar, ‘The Impact of Limited Forensic Capacity on Criminal Justice Outcomes in South Africa’ (2017)
30 Acta Criminologica: African Journal of Criminology Victimology 1, 9-15.
