DNA testing is a common procedure in a number of criminal cases across the country. While it can often be especially helpful in cases related to rape and/or murder, it can also be used to tie suspects to other crime scenes. Many jurors are under the impression that DNA matches are often irrefutable, and will often use those results to return a conviction for a crime. However, recent research has demonstrated that DNA may not be as reliable as once thought, especially in jurisdictions that have a backlog of DNA testing to complete. A recent article in The Atlantic looked into inconsistencies in DNA testing as it relates to criminal trials, and the results may be surprising.
Misinterpretation of Genetic Evidence
The article itself focused on the Houston Police Department Crime Laboratory, which handles approximately 500 DNA samples a year. One particular sample that was handled by the police laboratory dealt with a rape allegedly committed by two teenage boys. The DNA samples did not implicate one of the suspects, but indicated that DNA samples retrieved from the victim were consistent with that of the other suspect. The suspect whose DNA was consistent based on the test was sentenced to 25 years for aggravated kidnapping and sexual assault. Believing that her son was innocent, the suspect’s mother contacted local television reporters that had done a recent story on DNA inaccuracies from the Houston Police Department Crime Laboratory. She was then put into contact with a professor that had been researching DNA discrepancies for decades.
When the professor received the related reports and other information regarding the DNA sample of the suspect, there was an immediate glaring inconsistency. The suspect had given two blood samples and a saliva sample, from which DNA markers should have been consistent in each. However, there were a number of notable inconsistencies with the suspect’s personal DNA markers from the three different samples. This caused the professor to wonder how it was possible to get an accurate DNA profile from a mixed sample from the victim which contained several different DNA profiles when the laboratory technician was not able to obtain a consistent sample from the suspect. Further concern was generated when reviewing the report and noting that the suspect’s DNA sample did not match a semen sample taken from the back of the vehicle where the sexual assault had occurred. If the suspect had been the perpetrator and his semen was found in the back seat of the vehicle where the assault had taken place, then there should have been genetic markers in that sample which matched that of the suspect.
Ultimately, new DNA testing that employed more accurate techniques revealed that the DNA sample from the semen in the vehicle where the attack took place matched a known felon, who later confessed to committing the crime with another accomplice. Neither of the original suspects were identified as the accomplice, and the suspect that had been sentenced to prison was released when his conviction was overturned.
Dealing with DNA Evidence
An experienced criminal defense attorney is well-versed in the potential inaccuracies in DNA evidence. While DNA evidence can often provide irrefutable proof of a suspect’s guilt in a specific crime, it can only do so when it is handled and analyzed as accurately as possible. Labs that are overworked or constrained by limited resources may accidentally mishandle important DNA evidence. When there are serious inconsistencies in DNA samples, it is possible to have them suppressed in a trial or to at least question them with veracity. We have experience working with clients facing a variety of criminal charges, including sexual assault and other crimes where DNA could be a factor in a trial. The sooner you contact an attorney with experience handling these types of cases, the sooner your attorney can begin reviewing and investigating the case against you, which may include potentially faulty DNA samples.