On 17 February 2016, three men were convicted by a South African court of killing a mother-of-three 17 years earlier. Judgement in this cold case followed a four-year investigation and a two-year legal battle. The judge accepted the combined evidence of three eyewitnesses, handwriting analysis provided by the police and a DNA investigation, which was conducted by forensic experts of the International Commission on Missing Persons (ICMP). The handwriting analysis and DNA results were categorized as circumstantial evidence, as opposed to the direct evidence of eyewitness testimony. Evidence comes in many forms, such as eyewitnesses, participants, documents, physical evidence, and scientific evidence, like fingerprints or DNA.  No matter the form, there are two basic kinds of evidence that may be admitted in court – direct evidence and circumstantial evidence. Direct evidence does not require any reasoning or inference to arrive at the conclusion to be drawn from the evidence. Circumstantial evidence, also called indirect evidence, requires that an inference be made between the evidence and the conclusion to be drawn from it.

Presenting DNA-based evidence in court therefore can be challenging, as errors in the collection and/or handling of the biological samples used for the DNA analysis can result in the exclusion of DNA evidence at trial. Similarly, if a lab contaminates the biological sample or is found to use unreliable methods, a judge may reject the DNA evidence at trial. Also, it isn’t always easy to explain advanced scientific methods in simple and accessible ways in the courtroom. However, it should be borne in mind that most laypeople are probably unfamiliar with the technical aspect of conventional post-mortem examinations and other types of forensic techniques (and would quite possibly find standard procedures off-putting if they were explained in too much detail), so DNA-based testing is not unusual in this respect. And the value of DNA-based testing is that it is incontrovertible. When a DNA match connects an individual to a place or an artefact, the conclusion is more compelling even than eyewitness testimony (since an eyewitness may be confused, biased or simply mistaken in a way that genetic data cannot be).

In the United States, the Innocence Project reinvestigates trials and judgements on the basis of DNA testing, in order to address instances where an individual may have been wrongly convicted. This has resulted in an astonishing 342 post-conviction exonerations, of which 337 were based exclusively on DNA evidence. More than 300 cases are still on the organization’s docket.

While a DNA match is scientifically conclusive, the absence of a match is not correspondingly conclusive in the legal sense – since there are circumstances in which DNA testing simply cannot be applied, for example when a body has been burned or is otherwise severely decomposed, making it difficult to extract an adequate DNA sample for testing. DNA isn’t a magic wand that makes it suddenly easy to solve crimes and convict criminals – but it is an invaluable aid to the judicial process and for this reason it is imperative that the law – and court protocols – keep up with the science. The provision of evidence based on modern forensic methods should have its place in the modern courtroom.

The DNA Policy Initiative, a civil-society led project, was founded in 2010 to address the imbalance between the legitimate needs of law enforcement and individual rights with regards to DNA collection and use. It aims to build global civil society’s capacities to engage in policy-making processes on the development of national and international DNA databases and cross-border sharing of forensic information and to protect human rights by setting international standards for DNA databases. Its Global Summary shows us that in 2014, only 64 countries had operational forensic DNA databases. DNA databases in Europe vary widely in size and in the requirements of the legislation adopted. DNA databases currently exist in 26 of the 28 European Union member states. A DNA database is being set up in Ireland, where legislation was adopted in 2014 and samples began to be collected in November 2015. Malta will also need to establish a DNA database to comply with the EU’s Prüm Decisions, which require all EU countries to set up DNA databases and implement automated sharing of DNA profile matches across borders, and has received some EU funding to do so. Additionally, EU countries must all implement data protection legislation in line with the EU Data Protection Directive.

Interpol maintains its own database for the purpose of criminal investigations, called the DNA Gateway. More than 158.000 DNA profiles have been submitted so far, by 73 countries worldwide. ICMP on the other hand created and still maintains its groundbreaking Online Inquiry Center. This secured database contains 150,000 genetic profiles obtained from relatives of the missing and government authorities worldwide. The ICMP database consists of over 90,000 blood reference samples obtained from families of the missing and over 50,000 post mortem samples submitted to ICMP from government authorities searching for missing persons. By matching the reference samples obtained from relatives of the missing to post mortem samples submitted to ICMP by government authorities, ICMP is able to assist in identifying persons missing from armed conflict, crimes against humanity, as well as natural disasters. Through the provision of DNA identity testing, ICMP has assisted in closing over 18,000 missing persons cases.

In light of the remarkable capacity of DNA to elucidate cases, DNA-based evidence should be court-admissible in courtrooms throughout the world. Despite numerous non-governmental and governmental initiatives, a global consensus to that extend hasn’t been reached yet and a lot of countries are lacking behind with the creation and implementation of forensic protocols and standards. Furthering respective domestic legislation therefore is paramount, in parallel with and in relation to the international efforts that are being made.

[Disclaimer: The views expressed in this article do not necessarily reflect the views of the author’s employer.]