When you are charged with a criminal offense, the prosecution and law enforcement will work together to collect evidence to use against you in court. In some instances, this involves obtaining information from other parties to help create a more accurate timeline, and in others, it includes gathering physical evidence linking you to the crime. Often, one of the most critical pieces of evidence is DNA. In Oklahoma City and throughout Oklahoma County, DNA evidence generally passes through state forensic laboratories and utilized in district court felony cases. While this evidence is often used in felony cases, including violent crimes, drug offenses, and sex crimes, it must be carefully collected, preserved, and analyzed. Errors in this process can result in the reliability of DNA, ultimately leading to legal challenges.  The following blog explores how the introduction of DNA evidence at your trial can impact the outcome and how an Oklahoma City felony defense lawyer can assist you if you’re facing felony charges.

How Is DNA Evidence Used in Oklahoma Criminal Investigations and Trials?

In Oklahoma criminal cases, DNA evidence can be used during the investigation or to determine charging decisions and negotiations. Law enforcement collects biological samples from the crime scene to compare them to suspects and databases. In many Oklahoma cases, DNA evidence is analyzed by the Oklahoma State Bureau of Investigations (OSBI), which then sends results to the Oklahoma County District Court’s prosecutors.

When a suspect is in custody, DNA testing can be done to determine if they are a match for the samples collected at the scene of the crime. If the sample is not a match, the police may let the suspect go. If it is, they can be charged with the crime, as the DNA collected at the scene is theirs, thus placing them at the scene of the crime.

In some crimes, the DNA collected at the scene will be run through a database by law enforcement. This system, known informally as CODIS, will compare the sample to that of all convicted criminals who have had samples taken and input into the database. As such, the police can look for a match to determine if that person is responsible.

Common Types of DNA Evidence Collected

  • Blood stains
  • Saliva
  • Skin cells
  • Hair with roots material
  • Semen and other bodily fluids

How DNA Evidence Is Presented at Trial

In most Oklahoma felony trials, DNA evidence is generally introduced through expert testimony from a forensic analyst, meaning the prosecution must:

  • Establish proper collection methods at the scene of the crime
  • Prove the forensic analyst is qualified to testify as an expert witness
  • Show full compliance with the chain of custody requirements
  • Prove the laboratory testing methods were accurate and comprehensive

Can DNA Be Wrong or Misleading?

Yes, DNA evidence can be erroneous or misleading if the collection, storage, and testing procedures are flawed. While DNA science is incredibly advanced, errors can impact reliability in criminal cases.

Though many believe that DNA science is exact and foolproof, this is far from the case. In some instances, errors can occur, resulting in someone being charged with a crime they did not commit. Contrary to popular belief, DNA is not always definitive proof of someone’s guilt. Instead, it establishes biological presence, not when or how the DNA evidence was left there.

Common Sources of DNA Errors

  • Contaminated collection swabs
  • Improper storage methods
  • Mislabeling samples
  • Degraded DNA profiles
  • Mixed interpretation errors
  • Overstated statistical probabilities
  • Cross-contamination

Situations Where DNA May Not Prove Guilt

  • Secondary transfer
  • Innocent presence at a shared location
  • DNA deposits long before the crime occurred
  • Identical twins (indistinguishable DNA profiles)

Your Rights Regarding DNA Collection in Oklahoma

It’s important for those in and around Oklahoma City to understand that they have constitutional protections regarding searches and seizures. As such, the police need a warrant, consent, or a court order to collect DNA evidence. Additionally, this evidence may be obtained following a lawful, qualifying arrest. Under the Fourth Amendment, warrantless DNA collection can be challenged, depending on the circumstances of the collection.

Why You May Be Required to Provide DNA

  • Following a qualifying felony conviction
  • As a condition of probation
  • When a signed court order requires you to do so

When You May Be Able to Refuse DNA Collection

  • During voluntary police encounters
  • When probable cause is insufficient
  • When law enforcement has no probable cause or lawful court order

How Can an Oklahoma City Defense Attorney Challenge DNA Evidence?

If you are facing a felony charge and there is DNA evidence against you, it’s important to understand that hope is not lost. Working with an experienced criminal defense attorney can help give you the best chance of a favorable outcome.

Chain of Custody Challenges

  • Missing or incomplete transfer documentation
  • Gaps in evidence logs
  • Improper sealing or handling of evidence containers
  • Evidence is stored in unsecured locations

Laboratory Procedure Challenges

  • Accreditation of the facility or lab where the DNA was processed
  • Analyst training and certification
  • Past disciplinary history of laboratory technicians
  • Improper testing methods

Statistical Interpretation Challenges

  • Prosecutor’s fallacy
  • Overstating match certainty
  • Misleading juries about random match likelihood

Can DNA Evidence Help the Defense?

In some instances, the DNA evidence gathered can be the strongest evidence a criminal defendant is able to obtain. In fact, many wrongful conviction cases show that DNA evidence can be used to successfully exonerate an individual of the allegations against them.

How DNA May Strengthen Your Case

  • Excludes you as a contributor
  • Shows that an unknown third-party was present
  • Undermines unreliable witness statements
  • Can support alibis

Contact an Experienced Oklahoma City Felony Defense Lawyer Today

At the Jones Firm, PLLC, we understand how complicated these matters can be, which is why we will do everything possible to help you navigate these uncertain times. Connect with us today to learn how we can fight for you.