Katherine Winfree, Maryland’s chief deputy attorney general, told the justices that the state did not need to obtain a warrant to collect DNA samples from arrestees because people in police custody have already surrendered a substantial amount of their liberty and privacy.
“That can’t quite be right,” Justice Elena Kagan countered. “Assume you’ve been arrested for something; the state doesn’t have a right to go search your house for evidence of unrelated crimes.”
She added: “Just because you’ve been arrested doesn’t mean that you lose your privacy expectations ... that aren’t related to the offense that you’ve been arrested for,” Justice Kagan said.
“What we’re seizing is not evidence of crime,” Ms. Winfree responded. “What it is is information related to that person’s DNA profile.”
One issue in the case is the purpose of collecting the DNA. Maryland uses it to help identify the arrestee, Winfree said. But the state also uses it to solve unsolved crimes.
Justice Sonia Sotomayor picked up the same line of questioning. “You are going to have to tell me why searching their person is different than searching their home or car,” she said.
Winfree replied that people in police custody have a reduced expectation of privacy that eliminates Fourth Amendment protections for a person’s DNA. Collecting the DNA sample, she added, is minimally intrusive, involving a buccal swab from the inside of an arrestee’s cheek.
Michael Dreeben, deputy US solicitor general, told the justices that taking a DNA sample was substantially different from searching a home for evidence of a crime. “It is far more like taking a fingerprint,” he said.