In the past twenty years, advances in forensic DNA technology have revolutionized the American criminal justice system. DNA analysis not only has the power to exonerate the innocent, it also has the potential to eliminate suspects in many cases as well. A recent article in the Science Section of Thursday’s New York Times shows that it also helps apprehend the guilty. The article discusses an investigative technique called "surreptitious sampling" where law enforcement officers tail a suspect until he or she discards an item like a cigarette butt, a soda can, a disposable coffee cup, a tissue or similar trash that the officers can use to retrieve a DNA sample for comparison to DNA recovered at a crime scene. This method of gathering evidence also includes giving a suspect a can or glass during interrogation and keeping it to test for a DNA sample.
Critics claim this practice constitutes an unreasonable search and seizure under the Fourth Amendment and therefore violates the privacy rights of the accused and of citizens in general. However, some courts have held that such DNA material was abandoned when the suspect threw away the cigarette or coke can and that there is no need for a court to approve such evidence gathering or issue any type of warrant. In 2007, the Appeals Court of Massachusetts, in Commonwealth v. Cabral, 866 N.E.2d 429, held that the a defendant had no reasonable expectation of privacy in his saliva that he spit on the sidewalk and that the DNA evidence collected from the sample was admissible. Other lower court judges generally agree with such reasoning. How the US Supreme Court will address the issue is discussed in a 2006 article in the Journal of Law, Medicine & Ethics entitled “Is Obtaining an Arrestee’s DNA a Valid Special Needs Search Under the Fourth Amendment? What Should (and Will) the Supreme Court Do?”
As the NY Times article suggests, there will be a number of different approaches to this problem in years to come. Permitting the use of evidence gathered through surreptitious sampling may require that law enforcement meet a standard of reasonable suspicion. Adding this requirement would ensure that random people are not subject to such surreptitious sampling. Courts so far have sided with the police as it has long been accepted since the US Supreme Court case of California v. Greenwood, 486 U.S. 35 (1988) that the Fourth Amendment does not prohibit the warrantless search and seizure of garbage left outside of a home for collection based on a theory of reasonable expectation of privacy.