Genetic privacy, abandonment, and DNA dragnets: Is Fourth Amendment jurisprudence adequate?

Last week, you killed someone. You meticulously removed any evidence which might link you to the crime. You are still the prime suspect, but you're not worried. The police have nothing, not even probable cause to search your apartment. You are literally getting away with murder. But you have a nagging cold with an awful cough. On your way out the door one morning, you spit some phlegm on the sidewalk. A few days later, you find yourself under arrest and wondering what went wrong. This very scenario is currently playing itself out in Jacksonville, Florida. The police suspected an individual of murder, but were unable to obtain a search warrant. Undeterred, they trailed the suspect as he left his home, and when he spat on the pavement, they collected his saliva and tested it against genetic material found at the crime scene. A DNA match transformed the suspect into a murder defendant. Should the officers be lauded for their ingenuity in obtaining crucial evidence? Or should they be disciplined for shirking the warrant system intended to protect the constitutional rights of criminal suspects? Although the matter is not settled, existing case law suggests that the officers deserve praise. However, before such maneuvers become standard practice in criminal investigations, Americans would do well to examine the broader interests at stake. If we proceed without reflective pause, we risk the uncritical surrender of important civil liberties. The Case Law An individual's right to privacy during the course of a criminal investigation is constitutionally protected by the Fourth Amendment. However, this protection against unreasonable search and seizure is limited: the police may seize a piece of personal property without a warrant and use it as evidence if the individual is deemed to have legally "abandoned" the item. (1) Absent abandonment, police may obtain evidence only after demonstrating probable cause for a more personal search, requiring more than a bare suspicion, but not so much evidence as to justify a conviction. The touchstone for determining abandonment is whether the individual had a reasonable expectation of privacy in the seized property. Fourth Amendment protection is granted when a person had a sincere expectation of privacy in the disputed item (the subjective prong) and the expectation is one that society is prepared to recognize as reasonable (the objective prong). (2) In order to refute a claim that the property--in this case, genetic material--was abandoned, a potential defendant must show that he maintained a reasonable expectation of privacy in the seized item despite the appearance of abandonment. Since part of this test is subjective, the individual's intent is key, including the efforts he took to maintain the privacy of his property. (3) However, the potential defendant must also show that his beliefs about abandonment were objectively reasonable--that is, were beliefs that the typical reasonable person would have. Therefore, to protect his genetic material and prevent its admission as evidence under the law as it now stands, the defendant in the Florida case would need to show that when an average person spits on the sidewalk, sips a drink at a restaurant, or licks an envelope, he believes that his genetic material has not been abandoned. A strong challenge to such a demonstration will come from the "garbage cases." Courts have generally held that when garbage is located in a place accessible to the public, it is abandoned and its previous owner has forfeited any reasonable expectation of privacy he may have previously had. (4) A few decisions to the contrary have relied on the objective prong of the abandonment test to hold that society recognizes a reasonable expectation of privacy in one's garbage in proportion to the intimacy of the matter discarded. (5) This line of argument may be more promising to our Floridian defendant, as it allows use of a slippery slope argument about the way in which "abandoned" genetic material is used. …