On Monday, 57 protesters from the Black Lives Matter movement were arrested during a demonstration at the Thomas F. Eagleton Courthouse in St. Louis. Among them were Johnetta Elzie and DeRay Mckesson, two prominent activists who have campaigned against police abuses. Elzie and Mckesson, both prodigious users and consumers of social media, pointed out a peculiar aspect of their arrests after their release.
Did you know that when in the custody of the U.S. Marshal that they take two DNA swabs from your mouth to be sent to the FBI? I didn't.— deray mckesson (@deray) August 11, 2015
DNA swabs were wild. The woman marshal just told me to open my mouth and I had to ask her for what. She explained it 1st to the WW behind me— ShordeeDooWhop (@Nettaaaaaaaa) August 11, 2015
Since when can law-enforcement officials take DNA samples from citizens they arrest? The answer lies in Maryland v. King, a 2012 U.S. Supreme Court case that received little notice at the time, but carried significant Fourth Amendment implications.
First, some background. The Fourth Amendment prohibits unreasonable searches and seizures without a warrant, although the Supreme Court has ruled from time to time that there are exceptions in certain circumstances. The search-incident-to-arrest exception is one of the most significant: It allows law-enforcement personnel to search people they arrest without a warrant, and without the need to demonstrate probable cause. The Court outlined its rationale in the 1969 case Chimel v. California:
When an arrest is made, it is reasonable for the arresting officer to search the person arrested in order to remove any weapons that the latter might seek to use in order to resist arrest or effect his escape. Otherwise, the officer’s safety might well be endangered, and the arrest itself frustrated. In addition, it is entirely reasonable for the arresting officer to search for and seize any evidence on the arrestee’s person in order to prevent its concealment or destruction.
In 2009, Maryland expanded its DNA Collection Act to include individuals under arrest for certain serious crimes. DNA-collection efforts previously covered only those convicted and incarcerated, and the change raised new constitutional questions.