DNA Evidence and Collection Laws in Sexual Assault Cases in Texas

DNA as evidence

Texas courts highly value DNA evidence in sexual assault cases due to its accuracy and reliability. However, the process of DNA collection, testing, and interpretation is fraught with possibilities for error and contamination. Understanding how DNA evidence plays into Texas sexual assault cases is vital to mounting a robust defense.

If you are facing sexual assault charges in Texas, the experienced attorneys at Broden & Mickelsen, LLP can fight for your rights. Our lawyers are board-certified specialists in both criminal law and criminal appellate law, and we have the knowledge and skills to work for the most favorable outcome in your case. Contact us today for a free consultation to learn more about your legal options.

How Can an Experienced Texas Criminal Defense Lawyer Help in a Sexual Assault Case?

An experienced Texas criminal defense attorney is essential in protecting a defendant’s rights in sexual assault cases, particularly when DNA evidence is involved. From challenging the legality of DNA collection and testing procedures to scrutinizing the validity and interpretation of DNA results, your defense lawyer is your strongest advocate.

These legal professionals have a deep understanding of Texas’ laws and procedures. They may be able to find instances where law enforcement or laboratories have made errors or violated your rights. They can raise these issues and work on suppressing questionable evidence, leveling the playing field, and ensuring you receive a fair trial.

What Is DNA?

DNA, or deoxyribonucleic acid, is a molecule that carries most of the genetic instructions used in the growth, development, functioning, and reproduction of all known living organisms and many viruses. It is essentially the blueprint of life, carrying the genetic code that determines our physical characteristics and many other traits.

Except for identical twins, each person’s DNA is unique. This fact gives DNA its power as a tool for identification. When DNA left at a crime scene matches a suspect’s DNA, it can be powerful evidence. However, it is essential to understand that a DNA match does not automatically prove guilt. Other factors, such as the possibility of secondary transfer, can complicate the interpretation of DNA evidence.

Where Is DNA Found and How Is DNA Collected?

DNA can be found in almost every cell in the human body. It is most commonly collected from bodily fluids, such as blood and semen, or tissues, such as skin cells. In the context of a sexual assault investigation, DNA evidence may be collected from the victim’s body, the crime scene, or the suspect’s body or belongings.

Typically, professionals trained in forensic evidence collection gather DNA evidence using swabs, scrapings, or other techniques designed to capture and preserve these tiny, potentially case-altering pieces of evidence. They send this evidence to a laboratory for DNA extraction and analysis.

When Can Texas Law Enforcement Compel DNA Collection in a Sexual Assault Case?

In Texas, law enforcement can collect DNA from a person suspected of a crime under specific circumstances. For a sexual assault case, authorities can compel a DNA sample if probable cause exists that the suspect committed the crime. Under Texas law, law enforcement can take a DNA sample from any adult arrested for a felony offense. This means that if a person is arrested for sexual assault, law enforcement can take a DNA sample at the time of booking without a warrant or additional court order.

The collected DNA samples are typically stored in the Texas DNA database, also known as CODIS (Combined DNA Index System). This database allows for the comparison of DNA evidence from crime scenes with DNA samples collected from arrested and convicted individuals.

When a suspect is not under arrest, law enforcement may obtain a search warrant to collect a DNA sample. This process typically requires demonstrating to a judge that there is probable cause to believe that the suspect committed the crime and that the DNA sample will yield relevant evidence.

DNA May Not Prove You Committed a Crime

The presence of your DNA at the scene of a sexual assault does not always imply guilt. If a consensual sexual encounter occurred, your DNA might be present.

There may be other explanations for the presence of your DNA, such as secondary transfer, where DNA from one object gets onto another without direct contact. For instance, if a piece of your clothing carrying your DNA somehow ended up at a crime scene, it does not necessarily mean that you were at that location when the crime was committed.

If DNA from an unidentified or a different known individual is present at the scene or on the victim, it could bolster a defense case. This finding may suggest that someone else committed the crime. There have been numerous cases in Texas where individuals have been freed from prison after testing DNA that was not originally tested at the time of trial or re-testing original samples. These situations underscore the fallibility of relying solely on DNA evidence for a conviction and emphasize the need for competent defense representation.

Problems with DNA Collection in Sexual Assault Cases

The collection of DNA evidence requires meticulous care. Any minor error can result in contamination or loss of evidence. Some common problems include improper storage, mishandling of samples, and failure to follow protocols during collection.

DNA evidence can be contaminated in many ways, such as through the touch of an ungloved hand, coughing or sneezing over a sample, or mixing up samples. Contamination can also occur when DNA is transferred between items at a crime scene, which can mislead the interpretation of the evidence.

All this means that DNA evidence is not as straightforward as it may seem. Complex DNA mixtures involving multiple individuals, tiny amounts of DNA, or degraded samples can lead to errors in interpretation. Additionally, labs may make errors, or there could be bias in the interpretation of results. There have even been instances when lab techs have falsified reports and not tested DNA at all.

Besides issues with collection and interpretation, the defense can challenge DNA evidence on various grounds, such as the legality of the sample collection, the chain of custody of the evidence, and the credibility of the laboratory or expert witness.