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When Can Police Collect Your DNA?

By Tanya Roth, Esq. | Last updated on

You've probably seen TV crime shows where police follow a suspect around and collect cups that he's taken sips from, just to collect his DNA. But in reality, when is it legal for police to collect DNA from a suspect, and when is it crossing a legal line?

That's a common question on our FindLaw Answers Criminal Law forum. The ACLU has argued in the past that DNA is more invasive than a fingerprint and is a violation of privacy. But others say that it justifies the legitimate public interest of safety and the identification of criminal suspects. The Supreme Court, on the other hand, is actually set to consider the issue of police DNA collection in February. Until then, here are some quick facts on the topic:

One Court Says It's OK to Collect DNA From Someone Who Is Under Arrest.

There are legal arguments to be made for and against this practice. But at least one court, the Pennsylvania-based 3rd U.S. Circuit Court of Appeals, has ruled that police officers may collect DNA samples from a suspect who is under arrest. Why? Because arrestees already have a limited expectation of privacy.

Police Can Collect DNA Samples With a Warrant.

In many cases, police can collect DNA with a warrant. The warrant has to be issued by a judge. In order to obtain a search warrant, police have to show there is probable cause that a crime has occurred, and that evidence linked to the crime will more likely than not be found with the person or place that's the subject of the warrant.

That's still a tough call when it comes to DNA. Not every warrant will be deemed appropriate. There needs to be a "more likely than not" showing that the DNA from that person will yield evidence of the crime. That's a high standard, many would argue.

Can authorities collect DNA without a warrant?

That's a grey area, and ripe for Supreme Court review. The biggest debate is over a Maryland law that allows police to collect DNA samples from people who've been arrested for a crime, but have not yet been convicted. The theory is that incarcerated people already forfeit a certain number of Fourth Amendment protections.

But that law is facing a Supreme Court challenge, with arguments set for Feb. 26. We'll likely have a clearer picture about the issue of warrantless police DNA collection after the High Court issues its ruling.

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