Police officers are known to take discarded items and have them tested for DNA. In March of 2015, the Supreme Court decided not to hear Raynor v. Maryland, a case raising the issue of “surreptitious sampling” or the practice of testing discarded evidence. It seems well-settled, as the Supreme Court decided in 1988 in California v. Greenwood, that there is no reasonable expectation of privacy in discarded property.
If the police have probable case to arrest you for a serious criminal offense, you will be arrested, transported to a local jail, and booked in. The booking process includes identifying you by way of your fingerprints, county or state identification number, book-in photograph, and possibly a DNA swab. This DNA swab could then be run through a database called CODIS to determine if you are linked to any other criminal activity.
It has been argued that portions of the booking process, specifically taking a swab of your DNA, is a violation of your Fourth Amendment rights. Under the Fourth Amendment, you have reasonable expectation to privacy.
However, your privacy rights may be limited by significant governmental interests. The Supreme Court of the United States decided in Maryland v. King that the state has such a significant interest in the taking of your DNA during the booking process and that this interest is not outweighed by your privacy interest for the following two reasons:
The Supreme Court decision weighed the intrusion into a person’s privacy against legitimate law enforcement needs. The DNA sample in question was minimally invasive. Courts may come to a different conclusion with a different set of facts. Maryland v. King was a 5-4 decision, with Justice Scalia writing for the defense,
“The court’s assertion that DNA is being taken, not to solve crimes, but to identify those in the state’s custody, taxes the credulity of the credulous. … Solving unsolved crimes is a noble objective, but it occupies a lower place in the American pantheon of noble objectives than the protection of our people from suspicionless law enforcement searches.”
The analysis may change with a more intrusive DNA sample – such as drawing blood or sampling other body tissues or fluids.