When Alonzo King was arrested for assault in 2009 after pointing a shotgun at several people, authorities had no reason to think he was also a rapist.
Then officials swabbed his cheek at the Wicomico County, Maryland, booking facility and ran his DNA through a nationwide database. The check linked King to an unsolved 2003 rape.
Now King's conviction for the rape is set for argument next week at the U.S. Supreme Court, which will consider whether Maryland is violating the Constitution by collecting DNA samples from people arrested for serious crimes before they're convicted. The court's ruling, due by June, will be its first on the privacy of genetic information and will determine the fate of laws in at least 25 states that allow DNA collection at arrest.
"If the Supreme Court rules in favor of Maryland in this case, there will be no real limits on when the government can collect DNA," said Jennifer Lynch, a lawyer with the San Francisco-based Electronic Frontier Foundation, which opposes the collection laws. She said that would be a "huge privacy invasion."
Maryland argued in court papers that DNA gives police an invaluable investigative tool -- the "gold standard of forensic identification." Backers of the practice point to cases where DNA collection upon arrest might have prevented additional crimes.
One of those advocates is Jayann Sepich, whose daughter, Katie, was raped and murdered in August 2003, when she was a 22- year-old graduate student at New Mexico State University. Police weren't able to identify the killer, Gabriel Adrian Avila, until December 2006, after he was convicted and imprisoned for breaking into a house with a knife in an unrelated crime.
Jayann Sepich says Avila's DNA could have been collecte in November 2003, when he was arrested for the break-in. While Avila was convicted in 2004, he was released on bail before beginning his sentence and fled to Mexico. Not until Avila was arrested again in 2006 was his DNA tested, connecting him to Katie Sepich's murder.
"We got a bad guy and put him in prison," said Sepich. "We could have done it three years sooner."
Sepich now works full-time to advocate for DNA laws. She helped persuade the New Mexico legislature to enact what became known as Katie's Law, allowing for collection from anyone arrested for a violent felony.
Privacy advocates say there are more effective ways to get DNA to solve crimes that don't raise constitutional concerns.
Police currently collect DNA evidence from only a fraction of crime scenes, says Erin Murphy, a professor at New York University School of Law who specializes in forensic evidence. One study found that physical evidence, including DNA, was collected and submitted for testing in only 32 percent of U.S. rape cases and even less frequently in burglaries, robberies and assaults.
"We could have the biggest database in the world, and if we don't have crime-scene samples of good quality to compare them to, we're not going to solve crimes," Murphy said.
States could also add to their databases legally by collecting more samples from those who have been convicted of crimes, losing some of their rights, Murphy said. Court records indicate King had at least six prior convictions. The state could have collected his DNA by using his convictions, rather than the arrest, as the legal basis, she said.
"It's not the case that we've maxed out at what we can achieve with convicted offenders," Murphy said.
Until 2008, Maryland collected DNA samples only from people who were convicted of a felony. The state amended its law in 2008 to include anyone arrested for a crime of violence or burglary.
After taking a sample, Maryland ships it to a laboratory to create a profile -- a string of numbers almost always unique to that person. The state then submits the profile to CODIS, a national database maintained by the Federal Bureau of Investigation. The database allows comparison of the new profile to unknown DNA on file.
Maryland's highest court threw out King's rape conviction last year, saying the state had violated the Fourth Amendment ban on unreasonable searches. The court pointed to the "vast genetic treasure map" the state would be acquiring for each person arrested.
Maryland says it uses the DNA it collects only for identification purposes. The state also points to safeguards in the law, including requirements that samples be destroyed, with the records expunged, if a judge throws out the charges or the person is acquitted.
The Obama administration is backing Maryland in the case, which will be heard Feb. 26, likening DNA collection to fingerprinting -- a practice that is now routine procedure at intake centers, even though the Supreme Court has never ruled on its constitutionality.
"A DNA profile is only a list of numbers," U.S. Solicitor General Donald Verrilli argued in court papers. "Like a traditional fingerprint, it exposes nothing about a person's physical characteristics, propensities or medical conditions."
That's not the case, according to two genetic scientists backing King at the Supreme Court, Robert Nussbaum of the University of California San Francisco Medical Center and Sara H. Katsanis of Duke University. DNA profiles can already disclose family relationships and indicate the prospect of some medical conditions, such as Down syndrome, they say in court papers.
In the future, "advances in technology present risks that DNA profiling will become even more intrusive and will reveal more personal information about individuals," Nussbaum and Katsanis argued.
King's Supreme Court lawyer, Kannon Shanmugam, says Maryland and the Obama administration are seeking to short- circuit the usual requirement that police have reason to suspect a particular person before conducting a search.
While the Supreme Court has carved out exceptions to that rule -- giving officers more leeway to search parolees and letting police frisk a person for weapons at the time of arrest -- none of those exceptions apply to DNA, Shanmugam says.
"If the state's reasoning in this case were accepted, it would be difficult if not impossible to resist the conclusion that taking DNA from ordinary citizens would be permissible," said Shanmugam, a Washington lawyer at Williams & Connolly LLP.
Recent Supreme Court history suggests that argument may get a skeptical hearing. The court last year upheld the use of strip searches of newly arrested people, dividing 5-4 along ideological lines. And Chief Justice John Roberts may have dropped a hint about his leanings the Maryland DNA case in July, when he ruled that the state could continue collecting samples until the Supreme Court resolves the case.
"Collecting DNA from individuals arrested for violent felonies provides a valuable tool for investigating unsolved crimes," Roberts wrote, "thereby helping to remove violent offenders from the general population."
The case is Maryland v. King, 12-207.