Transferability of DNA in Florida Criminal Cases

September 5, 2025 Don Pumphrey, Jr. Sex Crimes, Violent Crimes Social Share

In Florida criminal cases, it is often assumed that the presence of DNA equates to a defendant being guilty. This is sometimes called the “CSI Effect” – if someone sees that DNA evidence indicates someone’s involvement in a criminal case, they are much more likely to support a conviction.

However, it is important to understand a frequently overlooked part of DNA testing in Florida criminal cases – the issue of transferability. DNA transferability refers to the ease with which a person’s DNA may be deposited in a particular location, simply by the defendant being located there rather than engaged in criminal activity.

Common examples may include:

• A accuses B of domestic battery. B lives in the same home as A. A DNA swab of A’s face reveals B’s DNA on it. The State attempts to introduce this as evidence that B hit A.
• P is accused of sexual battery on T, a minor, via the performance of oral sex. P lives with T. P’s face is swabbed and DNA is discovered – the State frames this as prima facie proof that P performed oral sex on T. 
• G, a felon, is accused of having illegally possessed a nearby firearm found in a group home. Law enforcement swabs the gun and finds a trace of G’s DNA on it. This is used as clear evidence that G touched the firearm (e.g. unlawful possession).

There are four primary considerations when evaluating the probative value (value in proving or disproving an allegation) of DNA evidence in a criminal case. These include:

• • Location: If someone’s DNA is found in a place they have allegedly never been (e.g. at a crime scene in New York when they were allegedly in Florida), DNA matches can carry weight. However, this depends on the odds of a random match.
  • Odds of randomness: The odds of a random match are relevant. For example, if the State says there is a “1 in 20” chance of a random DNA match, this means that 50,000 people in a group of 1 million would have also randomly matched. By contrast, if there is a 1 in 1 billion chance of a random match, this increases the probative (evidentiary) value of the DNA (almost certain that it belongs to the defendant).

• Transferability: The ease with which DNA may shed off of someone’s body. This is particularly relevant if the allegation stems from a place where the defendant is known to have lived or been.
• Type of DNA found: If epithelial cells (skin cells) are discovered, this generally does not have much probative value especially if it is undisputed the defendant was at a location or affiliated with the victim. However, discovery of specific types of DNA (e.g. sperm in a sexual battery case) may be more valuable.

It is critical to understand that the presence of DNA alone usually does not establish someone’s conclusive involvement in a crime. State v. Sephes, 262 So.3d 811 (Fla. 4th DCA 2019). This is because DNA is easily transferable and also often long-lasting (e.g. stays on items for many years after the interaction with it occurs).

In Sephes, Sephes (a felon) was accused of unlawful possession of a firearm. Sephes took off running after a traffic stop and when he was arrested, a firearm was found “near” his vehicle. Officers swabbed the gun and found Sephes’s DNA on it. Based partially on this finding of DNA, Sephes was charged (and convicted).

Sephes obtained a post-trial judgment of acquittal following a guilty jury verdict. Sephes argued that the transferability of DNA could have resulted in his DNA randomly having shed on the gun due to close proximity. Sephes also argued that he may have touched the gun years before he was prohibited from possessing it, but a DNA swab could not determine this. The judge agreed.

The State appealed the trial court ruling. Florida’s 4th District Court of Appeal affirmed that the trial court applied the correct legal standard in determining that “DNA alone” could not support a conviction in the case. The court cited the transferability and the Florida Supreme Court’s ruling in Hildwin, which reversed Hildwin’s murder conviction based on inadequacy of DNA evidence. Hildwin v. State, 141 So.3d 1178 (Fla. 2014)

However, the Sephes court ultimately reinstated the guilty verdict rendered against Sephes by the jury because there was other evidence (aside from the presence of DNA) that tied him to the gun. The court held: 

“There is a difference between putting pieces of a puzzle together and stacking inferences and assumptions. In this case, there were multiple pieces of evidence for the jury to consider to link Defendant to the crime. We are not persuaded by Defendant’s argument that impermissible inference stacking would have to be used for the jury to find Defendant guilty beyond a reasonable doubt.”

Sephes holds that if DNA is the only thing tying a defendant to the alleged crime, and the State’s remaining evidence requires “pyramiding of assumptions or inferences in order to arrive at the conclusion of guilt,” the DNA’s presence alone cannot serve as the basis for conviction. Brown v. State, 672 So.2d 648, 650 (Fla. 4th DCA 1996). This is largely due to its transferability.

Returning to the example cases, we can see how Sephes and the issue of DNA transferability generally can impact the outcome of a criminal proceeding:

• A accuses B of domestic battery. B lives in the same home as A. A DNA swab of A’s face reveals B’s DNA on it. 
• P is accused of sexual battery on T, a minor, via the performance of oral sex. P lives with T. P’s face is swabbed and DNA (skin cells of T) is discovered on his face.
• G, a felon, is accused of having illegally possessed a nearby firearm. Law enforcement swabs the gun and finds a trace of G’s DNA on it.

In each of these cases, an experienced Florida criminal defense attorney can (and likely should) run a motion to suppress the admission of DNA evidence on the basis that the danger of unfair prejudice substantially outweighs its probative value (Fla. Stat. 90.403). 

Since DNA is extremely transferable, there is a very plausible explanation for how the DNA in each of these cases may have ended up where it was found:

• B’s DNA was shed on A while they shared a bed or otherwise interacted physically.
• T’s DNA (skin cells) could have gotten on P’s face through any form of physical interaction including hugging or touching her clothing, if P then wiped his face.
• G’s DNA could have been on the gun from before he was prohibited from having it, or shed on the firearm incidentally (Sephes).

Because there is a clearly reasonable non-criminal explanation for how the defendant’s DNA arrived where it did in each of these hypotheticals, a court may find that admitting the “DNA evidence” would not prove much of anything regarding the allegedly criminal activity. Thus, it may be excluded.

However, there are cases where the discovery of a defendant’s DNA is considered much more probative (having evidentiary value) than the above examples. These may include:

• C is accused of murder in Florida. He claims he has never been to Florida. However, C’s DNA was found on the murder weapon with random match odds of 1 in 1 billion.
• L is accused of sexual battery on A. L claims to have never met A, but DNA testing finds L’s semen was on A – with a 1 in 1 trillion chance of a random match.
• M is charged with armed robbery, and is alleged to have been wearing a mask. M says he was in Italy at the time. However, police find M’s DNA on the mask, with a 1 in 10 trillion chance of a random match.

In these examples, it is clear that the transferability of DNA is not truly a factor. This is because the DNA was found in a place or a specific type of DNA was found that is essentially impossible to have been discovered if the defendant did not commit the offense.

In sum, transferability of DNA can have a major role in Florida criminal cases. If DNA (especially skin cells) is found in an unsurprising location, this has less probative (evidentiary) value than most people believe due to the ease with which DNA transfers (sheds) onto surrounding objects or individuals.

In cases where DNA is being heralded as a major piece of evidence, it is worth taking a second look and evaluating whether this is a strong indicator of guilt or not. If the probative value of the State introducing DNA evidence at a trial is outweighed by the danger of unfair prejudice (Fla. Stat. 90.403), a Florida defense attorney can move to suppress this – citing transferability.

If someone is arrested and formally charged in Florida and concerned about whether they qualify as a family member or custodian for enhancement purposes, or are challenging DNA evidence, it is critical to find experienced and trusted legal representation as soon as possible. This decision could make the difference in whether or not someone faces a lengthy prison term and hefty fines.

Criminal Defense Attorney in Tallahassee, FL

Don Pumphrey, Jr. is a Former Prosecutor, Former State Police Officer, Lifetime Member of the Florida Association of Criminal Defense Lawyers; for over 25 years as a private defense attorney who is Trusted, Experienced, Aggressive in Criminal Defense as a Trial Attorney, Criminal Lawyer, Criminal Defense Lawyer for the accused in Florida State Courts located in Tallahassee, Florida but handling cases throughout the State of Florida.

Don Pumphrey, Jr. and the Tallahassee criminal defense lawyers at Pumphrey Law have decades of experience fighting drug charges on behalf of clients and winning. Call Pumphrey Law now at (850) 681-7777 to learn more about what we can do for you. Our lawyers will be happy to provide you with a free consultation.

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