How Reliable is DNA Evidence? Problems and Defense Options

how reliable is dna evidence

You’ve seen this on TV before. A forensic analyst marches into a room where colleagues are discussing a case. The analyst then tosses a tiny evidence bag with a couple of hairs inside it onto the table and says something like, “We’ve got them. We have DNA.” That’s great TV. It’s not entirely correct, though.

While DNA evidence is often accurate and leads to hundreds of solved crimes every year, it’s not the end-all, be-all of criminal prosecution. In fact, DNA evidence is often involved in wrongful convictions. For instance, since 2018, the National Registry of Exonerations has recorded 26 overturned wrongful convictions that involved DNA evidence — and that’s just the ones that were overturned. Hundreds more people could be wrongfully behind bars right now due to faulty evidence.

How reliable is DNA evidence? Not reliable enough to justify many convictions. If you’ve been charged with a crime based on DNA evidence, the team at Will & Will can defend you. Read on to learn about problems with DNA evidence in court, or get in touch with our firm to learn more.

What Is DNA Evidence?

The DNA of all human beings is almost identical. From person to person, there are only tiny differences. These differences define our genetics — they say who we are. 

DNA evidence is forensic evidence that uses your unique genetic profile to suggest whether you were in a particular place, touched a particular object, or committed a certain crime. DNA profiling is a relatively new advancement in forensic science. The first arrest based on DNA evidence happened in 1987. Since then, the use of DNA has grown sharply.

DNA can come from blood, hair, semen, saliva, skin tissue, bones, teeth, and fingerprints. According to the Revised Code of Washington, Section 5.70.010, DNA evidence can be obtained through sexual assault kits, via crime scene investigation, or by police in the course of an investigation. 

Uses of DNA in a Legal Setting

Since science identified DNA as a way to tell people apart, DNA has become widely used in the legal system. For instance, it may be involved in the following settings:

  • Criminal prosecutions for active cases
  • Solving cold cases
  • Proving paternity in family courts

But how reliable is DNA evidence used in legal settings? Many of those accused of a crime are aware of how DNA is used in criminal cases. And that, of course, makes you nervous even if you didn’t commit the crime. What if your DNA shows up in the investigation but only because you had been to the crime scene before? There are a million ways your DNA could get somewhere. Is that enough to convict you of a crime?

Is DNA Evidence Enough? Potential Problems

It’s important to understand this: DNA is not always reliable. There are plenty of problems with DNA evidence in court. If the police have DNA evidence that suggests you committed a crime, that’s not good. It also certainly does not prove that you did it, and a good lawyer can help you expose the problems with the DNA evidence against you.

Just because DNA can be highly accurate doesn’t mean it always is. The following factors can render DNA evidence inaccurate. This means a lawyer could help you get it excluded from your trial provided that:

  • There’s not enough DNA to get a reliable sample 
  • There were errors in collecting the DNA
  • There was an improper handling of the DNA after it is collected
  • There was an inaccurate analysis of the DNA in the forensics lab
  • There was a failure to preserve the DNA used as evidence to support a charge, per Revised Code of Washington, Section 5.70.020
  • There was a failure to preserve the DNA used as evidence after the conviction for 99 years after the fact, also per Washington state law

Defense Options Against DNA Evidence

Prosecutors would love for you to believe that DNA evidence is perfect proof that you’re guilty. They want you to give up fighting the charge and admit to the crime so they can close the case. 

Fortunately, there are ways DNA evidence can be challenged, such as:

  • Reasonable doubt. Even under the best conditions, DNA profiling is never 100 percent accurate. But to convict you, the jury must have no reasonable doubt that you committed the crime. Your lawyer can put doubt in the jurors’ minds by debunking the myth that DNA is always right.
  • Exposing problems with the chain of custody. Any evidence, including DNA, has to follow a strict chain of custody after it’s collected. If the DNA being used against you went into the wrong hands or place for even a second, that could be enough to get it thrown out.
  • Questioning the technology. Different counties and cities have different equipment and labs for DNA analysis. Some are much better than others. If it’s even remotely possible that the lab’s processes weren’t up to par, that could be reason to exclude the DNA evidence against you.

Challenging DNA evidence is possible, but it isn’t easy. That’s why it’s so important to speak with an experienced criminal defense lawyer who knows how to expose problems with DNA evidence.

Accused of a Crime Using DNA Evidence? Let Will & Will Defend You

How reliable is DNA evidence? It depends on a lot of factors, but the bottom line is that you can fight this charge even if there’s DNA evidence against you. The trusted attorneys at Will & Will are ready to help.With decades of experience, we’re prepared to add you to our long list of clients who have gotten their lives back. We know our way around DNA, and we know how to fight any charge based on it. Ready to get started? Call 206-209-5585 or contact us online.

How can we help?

  • We only handle cases in Washington State. What City/County is your case located in?