The DNA Abandonment Doctrine in Florida Criminal Cases

September 5, 2025 Don Pumphrey, Jr. Criminal Defense Social Share

The abandonment doctrine allows law enforcement to test for someone’s DNA in an effort to match them to biological material found at a particular scene even without a warrant or consent. But when does this doctrine actually apply in Florida?

The answer is – police may gather and test “abandoned” DNA if it is left behind in a place or on an item where the suspect does not have a reasonable expectation of privacy. This blog will explain the abandonment doctrine and its practical application to the collection and use of DNA evidence in court.

In Florida, it is frequently thought that someone must either consent to police collecting their DNA – or law enforcement must get a warrant – for this evidence to be admissible in court. But in some cases, DNA evidence obtained by neither of these means can be used against you. This is called the “abandonment doctrine.”

The foundation for the abandonment doctrine was laid in the U.S. Supreme Court case California v. Greenwood, 486 U.S. 35 (1988). There, police rummaged through Greenwood’s trash that he had placed on the sidewalk and found incriminating evidence. Greenwood was arrested and later convicted.

Greenwood challenged the collection of evidence from his garbage, arguing this violated his Fourth Amendment right against unreasonable searches and seizures. But the U.S. Supreme Court ruled against him. It found that because Greenwood had abandoned any “reasonable expectation of privacy” when he took his trash to the curb, law enforcement could search it.

Courts have applied this principle to the collection of DNA evidence. A recent case involving the abandonment doctrine in the context of DNA is the 2022 Idaho University killings. The suspect, Bryan Kohberger, recently pled guilty and is serving a life sentence.

Investigators initially extracted DNA from the knife sheath Kohberger left at the scene, but it did not produce a match in the system. As they began to suspect Kohberger, law enforcement went through the garbage outside his family’s Pennsylvania home and swabbed an item. It revealed the presence of DNA that was a “familial match” to Kohberger.

This evidence was considered “fair game” under the abandonment doctrine. Though Kohberger himself was the target of the investigation (not his family), prosecutors argued the DNA evidence was permissibly collected (both from the knife sheath and the trash). The court agreed, denying the defense’s motion to suppress.

But when does abandonment truly occur? Florida’s courts have been asked to answer this question in many cases. In essence, whether DNA (or other biological evidence such as blood, hair, etc.) has been “abandoned” is evaluated based on the totality of the circumstances. Hargrove v. State, 412 So.3d 817 (Fla. 6th DCA 2024)

Hargrove stated that “the test for abandonment is whether a defendant voluntarily discarded, left behind, or otherwise relinquished his interest in the property in question so that he could no longer retain a reasonable expectation of privacy with regard to it at the time of the search.” 

Factors used to evaluate this may include the location of the discarded property and the manner in which it was discarded (e.g. accidentally or intentionally). 

Critically, Hargrove held that the question of whether DNA is abandoned does not hinge on the subjective intent of a suspect, but whether they could have objectively retained a reasonable expectation of privacy as to the DNA/the item it was located on. 

Hargrove acknowledged this was a departure from some past cases (such as State v. Kennon) which placed emphasis on the defendant’s mindset. For example, if someone leaves a soda can on a table in a public place and forgets about it (without explicitly intending to dispose of it), the Hargrove would consider this “abandoned” despite the lack of explicit intent to leave it behind.

Put simply, law enforcement can test an item of interest for DNA that appears to have been voluntarily abandoned in an area where the defendant does not have a reasonable expectation of privacy. When the item is left in an area without a reasonable expectation of privacy, Hargrove holds there is no Fourth Amendment protection.

Examples of abandonment under this relatively broad Hargrove standard include:

• Tossing a cigarette butt on the sidewalk (no reasonable expectation of privacy in a public place, voluntarily discarded)
• Leaving an open water bottle behind at a table outside a restaurant and neglecting to throw it away
• Throwing a napkin or a tissue into a public garbage can

Examples of acts that do not constitute abandonment for purposes of allowing law enforcement to collect it include:

• A drink can you left on your patio (on your property, law enforcement would need a warrant or consent)
• A coffee cup left in your office cubicle (private area)
• A tissue sticking out of your back pocket while walking through a public area (has not been discarded yet, so no abandonment)
• DNA collected from a hospital blood draw without consent or warrant (medical use does not create abandonment)

Once police obtain your DNA (legally), this is not limited to use in the criminal investigation for which the DNA is collected. If someone becomes a suspect in a separate probe, police may test the DNA that was obtained as part of a previous investigation to determine a suspect’s potential involvement. They do not need to get a new DNA sample. Wyche v. State, 987 So. 3d 23 (Fla. 2018)

Given the above, there are three ways police can legally obtain someone’s DNA in a criminal investigation in Florida:

• Warrant: Police obtain a lawful (Fourth Amendment-compliant) warrant from a judge to obtain a DNA sample from a suspect or item.

• Consent: Someone consents (if not a product of coercion or threats) to officers collecting their DNA. Under Wyche, law enforcement can lie to a suspect as to why their DNA is being sought, as someone does not feel they are being threatened or coerced to give a DNA sample.

• Abandonment: If someone leaves behind DNA on an item (e.g. a soda can or in a trash bag) located in an area where they have no reasonable expectation of privacy, it is considered abandoned – allowing police to obtain a sample without a warrant or consent.

Note: Florida law provides that someone convicted of sex crimes, other felonies and certain misdemeanors must provide their DNA to the State (Fla. Stat. 943.325). This DNA can be used in future criminal investigations regardless of the donor’s consent.

If someone’s DNA is obtained by law enforcement as evidence in Florida and the State seeks to introduce it, there are many potential grounds upon which to exclude this from use in court. These may include:

• Daubert challenges: If the DNA was collected or analyzed using insufficiently reliable methods, or if expert testimony regarding the DNA evidence is found to be unreliable or not generally accepted in the scientific community, the evidence/testimony may be excluded from use in court (Fla. Stat. 90.702).
• 90.403 challenges: Otherwise relevant evidence can be excluded from presentation in court if its probative (evidentiary) value is substantially outweighed by the danger of unfair prejudice, confusion, misleading the jury, or needlessly cumulative presentation of evidence. This includes DNA (Fla. Stat. 90.403).
• Illegally obtained evidence: If the DNA sample was unlawfully obtained through a faulty warrant (false representations to the court, etc.), force or coercion to get “consent” from a suspect, or through a misapplication of the abandonment doctrine, this may be suppressed (pursuant to Wong Sun v. United States, 371 U.S. 471 (1963)).
• Chain of custody challenges: If the defense makes a showing of probable tampering, contamination or mishandling of DNA (due to chain of custody issues), this must be disproven by the State before DNA evidence is considered admissible. The defense must allege specific facts showing tampering was more likely than not. Murray v. State, 838 So.2d 1073 (Fla. 2002)

In sum, the abandonment doctrine holds that law enforcement can obtain a suspect’s DNA without their consent or a warrant, so long as the suspect no longer has a reasonable expectation of privacy. This is determined based on the totality of the circumstances and is an objective test (e.g. someone saying “I didn’t mean to leave the item behind” can’t alone render the collection illegal).

If law enforcement improperly applies the abandonment doctrine, this can serve as grounds for a motion to suppress or exclude DNA evidence. Other grounds to do so include challenging the DNA chain of custody, Daubert challenges, moving to suppress or exclude based on Fla. Stat. 90.403, and more.

If someone is arrested and formally charged in Florida with an offense and is concerned about 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.

  Social Share