DNA is a form of biological evidence found in almost every cell of the human body. DNA testing is one of the most powerful tools in the pursuit of justice, particularly in the case of rape or sexual assault.  But South Africa is grappling with a staggering backlog of DNA backlog on 140,000 rape cases, raising serious concerns about the efficiency and responsiveness of the forensic system. Dr Vanessa Lynch, is the regional director for DNAforAfrica, a company that works around forensic DNA profiling. Health-e News speaks to her about the urgent need to strengthen forensic processes.

How does DNA work in criminal cases?

DNA helps link a suspect to a crime scene by using biological evidence such as saliva, blood, hair, or skin. In rape cases, which often involve close physical contact and sometimes injuries, this kind of evidence is especially important. DNA can be found on the victim, and sometimes on the suspect too, helping to show that the two people were in contact.

However, DNA on its own doesn’t prove someone is guilty. It just shows that they were present. It’s up to the prosecutor to decide whether the contact was consensual or not. If the details of the case suggest that it wasn’t consensual, the court must then determine whether rape occurred. 

DNA is collected using a sexual assault evidence collection kit commonly known as a sexual assault kit. However, there is a shortage of rape kits in some police stations.  These kits include several tools, but one of the most important is a swab. Medical professionals use these swabs to collect samples from the victim’s body, especially in areas where biological evidence like saliva, blood, or skin cells is likely to be found, depending on the nature of the assault and any injuries. Forensic nurses or doctors specially trained to handle sexual assault cases carry out the examination. The collected samples are then sent to a lab for DNA analysis.

South Africa has a strong DNA Act that allows authorities to store DNA profiles in a national database –  even if there is no known suspect at the time. This has been incredibly useful, especially as technology has improved. 

In some cases, DNA profiles are now being matched to crimes committed 40 years ago.

Modern DNA technology is so sensitive that even the smallest trace of DNA can often produce a usable profile.

What are the challenges of DNA testing in South Africa?

DNA testing uses strict rules, or thresholds, to ensure accuracy. 

As technology improves and becomes more sensitive, it also picks up more background noise, known as “artifacts,” which can be mistaken for real DNA. For example, older tests needed a signal of at least 50 RFU (a measure of strength) to count as real. Newer tests might need a higher threshold, like 175 RFU, to avoid false results. If the threshold is too low, fake signals could be included. That’s why setting the right threshold is so important.

One major challenge in South Africa is the lack of advanced software known as probabilistic genotyping software. 

This software helps calculate the likelihood that a DNA sample matches a suspect, especially in complex cases involving mixed DNA from more than one person.

Currently, the Forensic Science Laboratory uses STR (short tandem repeat) labs and DNA view for complicated family relationship (kinship) calculations. But without the newer software, forensic officers still have to manually compare mixed DNA samples to those taken from individuals, like buccal (cheek) swabs. 

This is part of their job, but it’s time-consuming and not always as precise.

To implement the new software, labs would need stronger computers and new servers. 

What has led to the high DNA backlog in South Africa?

The DNA backlog is one of the most frustrating issues facing the justice system today. Currently, there are around 140,000 rape cases stuck in the system but the real number may be even higher. The Forensic Science Laboratory has admitted to this backlog, yet failed to present a proper recovery plan to the DNA Board.

There are several reasons for this crisis. 

Key issues include delays in procurement where tenders have been awarded, but equipment and supplies such as forensic equipment and machines  have not been delivered, as well as poor maintenance of essential lab equipment. On top of that, there appears to be a serious management crisis within the forensic science services.

The Chairperson of the Portfolio Committee has called on the Auditor-General to investigate the forensic labs, expressing deep concern over the lack of progress and transparency. The truth is, that South Africa has excellent scientists and access to strong DNA technology. With our capabilities, there should be no excuse for such extreme delays that has been happening since 2019. 

This is not acceptable, and it urgently needs to be addressed.

How do DNA backlog cases affect the justice system?

The DNA backlog has a serious and damaging impact on the justice system especially in rape cases. Without timely DNA results, cases are often thrown out of court, and perpetrators remain free simply because they haven’t been identified.

DNA is a critical form of evidence in sexual assault cases, and without it, prosecutors may struggle to build a strong case. This causes long delays in justice and can leave survivors feeling forgotten or dismissed. For many, it adds insult to injury when their cases are not prioritised. It sends a painful message that justice for survivors is not being treated with the urgency and seriousness it deserves. – Health-e News