With the advent of DNA testing, numerous issues have arisen with regard to obtaining and using evidence developed from such testing. As courts have come to regard DNA testing as a reliable method for linking some people to crimes and for exonerating others, these issues are especially significant. The federal government and most states have enacted statutes that permit or direct the testing of those convicted of at least certain crimes. Courts have almost universally approved such testing, rejecting arguments that obtaining and using such evidence violates the Fourth Amendment.
More recently governments have enacted laws permitting or directing the taking of DNA samples from those arrested, but not yet convicted, for certain serious crimes. Courts had been far more divided about the constitutionality of DNA testing for arrestees than they were for the comparable testing of those already convicted of crimes. Given the division in the holdings among both state and federal courts and the increasing importance of DNA evidence in criminal investigations, it was hardly surprising that the Supreme Court agreed to hear a case regarding the constitutionality of a Maryland statute allowing for such testing.
Section II of this article will provide a brief description of the science of DNA testing as it is used in the criminal justice system. Section III will discuss the Supreme Court's decision in Maryland v. King. Section IV will address the argument of the opponents of the DNA testing of arrestees - that it violates the presumption of innocence. The chief focus of the article will appear in Sections V and VI, which will respond to the arguments posed by those who claim such testing violates the Fourth Amendment. Section V will address the balancing test for such searches and seizures long employed by the Supreme Court. Section VI describes and critiques the use of the primary purpose test as an important factor in determining whether the Fourth Amendment has been violated. This test looks to whether the primary purpose of the government's search or seizure was something other than to ferret out ordinary criminal wrongdoing, and only in such situations excuses the absence of individualized suspicion.
Using the DNA Testing of Arrestees to Reevaluate Fourth Amendment Doctrine, 49 Valparaiso U. L. Rev. (2014) (forthcoming)