Washington (CNN) -- On the back of Jayann Sepich's business card is her DNA profile, a reminder of the potential and pitfalls of technology at the heart of a privacy dispute now before the U.S. Supreme Court.
At issue is the constitutionality of a state genetic testing law. Maryland's DNA Collection Act permits police to collect genetic material without a warrant from those who have been arrested but not yet convicted of crimes. Some states allow testing for certain misdemeanors too, including sex-based offenses.
Sepich founded the group DNASaves.org after the murder of her 22-year-old daughter, a shocking crime unrelated to the current high court appeal. Her killer was not identified until three years later, after the man was convicted of a separate armed burglary. She now supports expanding databases to included arrested criminal suspects.
"My daughter gave up her most basic constitutional right -- the right to live," she told CNN. "There are so many heinous criminals that are being arrested, and not being identified as having committed these [other] crimes. They are being released and they re-offend. ... And we need to stop them earlier because they re-offend and they kill and they rape."
Fourth Amendment test
But privacy advocates warn a final ruling in the state's favor could open the gates to greater government use of one's biological makeup for a variety of non-judicial purposes.
"The Constitution says police must have some level of suspicion, and we know that intuitively," said Erin Murphy, a New York University law professor and national expert on forensics evidence. "If someone is arrested for drug possession, driving under the influence, writing a bad check, for jaywalking -- they don't have all their private information exposed to the police. The police have to have suspicion if they then want to then go search the individual" by taking the DNA sample.
The current case involves a Maryland man convicted of a 2003 rape in Wicomico County in the state's Eastern Shore region. Alonzo King Jr. had been arrested four years ago on an unrelated assault charge, and a biological sample was automatically obtained at that time. That sample was linked to the earlier sexual assault.
King moved to suppress that evidence on Fourth Amendment grounds, but was ultimately convicted of the first-degree rape offense.
Both King and his legal team turned down CNN's request for an interview.
A divided Maryland Court of Appeals later agreed with King, saying suspects under arrest enjoy a higher level of privacy than a convicted felon, outweighing the state's law enforcement interests. That court also said obtaining King's DNA immediately after arrest was not necessary in identifying him, and that the process was more personally invasive than standard fingerprinting.
State officials then asked the justices to intervene, saying the state court ruling "has resulted in the loss of a valuable crime-fighting tool relied upon by Maryland." They said that from a law enforcement and forensic perspective, there is no difference between fingerprinting and collecting "biometric information."
Chief Justice John Roberts last July allowed the Maryland law to stay in effect until a full appeal could be filed. The high court then agreed to decide the constitutional issues. Roberts at the time hinted his tentative support.
Oral arguments on Tuesday
"Collecting DNA from individuals arrested for violent felonies provides a valuable tool for investigating unsolved crimes and thereby helping to remove violent offenders from the general population," Roberts wrote. "Crimes for which DNA evidence is implicated tend to be serious, and serious crimes cause serious injuries. That Maryland may not employ a duly enacted statute to help prevent these injuries constitutes irreparable harm."
The chief justice said last summer there was a "fair prospect" the Supreme Court would ultimately find in favor of the state on the search and seizure questions. Oral arguments will now be held Tuesday, with a ruling expected by June.
A 1994 federal law created a national database in which local, state, and federal law enforcement agencies can compare and share information on DNA matches from convicted felons, but courts have been at odds on just when such samples can be collected and the information distributed.
"The (state court) decision below has direct effects beyond Maryland: Because the DNA samples Maryland collects may otherwise be eligible for the FBI's national DNA database, the decision renders the database less effective for other states and the federal government," Roberts wrote.
The state DNA collection law in Maryland is set to expire at the end of the year, but the justices are likely to decide its constitutionality before then.
Sepich recalls the day a decade ago when she learned her daughter had not returned from a party the night before.
Katie's body was found later that day in a Las Cruces city dump. She had been raped, strangled to death, and her body set afire. One of the graduate student's last acts was to preserve her killer's identity. Blood and skin of the killer was under her fingernails, as she scratched the man while fighting back from the attack.
That genetic profile was placed in a nationwide database known as CODIS. Three months after the murder, Gabriel Avila was arrested for a home break-in, but no DNA was taken. The Mexican national made bail and fled. Sepich says he was allowed to roam the streets for three years before his recapture and 2006 conviction prompted an automatic DNA swab.
Sepich and her family meantime tried to make sense of the murder and turn it into something positive, in Katie's memory.
"It was at that time I learned that DNA was not used like fingerprints. It wasn't taken upon felony arrest," said Sepich. "And I was so convinced of its effectiveness. That's when our family started our quest to see DNA taken upon arrest in all 50 states. Our home state of New Mexico did that in 2006 and we've just continued to work to see other states passed."
Just 11 months after Katie's Law was signed in New Mexico, Avila's genetic markers were linked to Katie's murder. He then pleaded guilty and was given 69 years behind bars. The prosecutor in that case is now New Mexico Gov. Susana Martinez, a Republican.
"What [this law] it means to me is that there are so many other mothers that will not bury their daughters." said Sepich. "That will have the joy of having them for the rest of their lives. And I know that sounds very emotional, but people say that if we could just prevent this from happening to one other person, but there's so much truth in that."
DNA samples taken during arrest
A legally complex case begins simply. Upon arrest, a criminal suspect-- along with a mugshot and fingerprints-- opens his or her mouth and a cotton swab takes a sample from the cheek. It is placed in a vial, given a number, and stored. No consent or warrant is initially required.
Twenty-six states and the federal government allow genetic swabs to be taken after a felony arrest. Each has different procedures, but in all cases, only a profile is created -- about 13 individual markers of some three-billion -- are isolated from a suspect's DNA.
That selective information does not reveal the full genetic makeup of a person, and officials stress, and nothing is shared with any other public or private party, including any medical diagnostics. The Obama administration has signaled its support.
Law enforcement says it works and point to Chester Turner, a Los Angeles man who was arrested 21 times over the years for non-violent offenses, but never had a DNA sample taken. But after a rape conviction, he was revealed to be a serial killer, linked to at least 10 unsolved murders of women, and the rapes of other victims. He was given the death penalty in 2007.
In a brief filed by 49 states supporting Maryland, officials also say the information is secure, and retested when an initial "hit" is identified. After a warrant is issued for probable cause, another fresh DNA sample is taken and it that test that is used to ultimately prosecute in court. Each initial test costs about $30.
Every Monday those markers are compared with CODIS samples newly submitted by states.
But there are also wide differences in how the DNA taken after arrest is used.
"In Maryland, when police arrest you, they can take but cannot test that swab, until there is probable cause for the arrest, meaning that the judge says this is a legitimate, legal arrest. In other states, that's not the case," said Murphy, noting California allows testing immediately after arrest.
"And another feature that's different in the Maryland law than some laws across other states, is that if the judge finds that there has been no support for the arrest, the state has to immediately destroy all samples and purge all records from its database," Murphy said.
Other states require the person who was arrested to petition the court directly, often a time-consuming and expensive process.
Privacy advocates weigh in
Privacy advocates also say blanket collection of everyone arrested for a felony -- even non-violent ones -- is not effective as a crime-fighting tool. Murphy says police typically only collect DNA from murders and sex-based crime scenes like rape, and that expanding the evidence chain would be a better use of resources, than a sweeping collection upon arrest. Some states acknowledge boxes of DNA swabs have gone untested.
"The use of DNA is expanding rapidly so many states now engage in a process called familial searching, to collect information about the possible profiles of an individual's family members," said Murphy. "It's also possible to take the DNA profile and gleam from that inference about a person's race or ethnicity. Those are types of private information that a fingerprint never could expose."
King's attorney Kannon Shanmugam told the high court, "There are over 12 million arrests in the United States every year. Virtually all of the arguments advanced by [Maryland] and the United States would justify the blanket collection and retention of DNA from ordinary citizens."
And civil liberties groups worry inadequate testing by overwhelmed lab technicians can lead to errors, like the one that sent Dwayne Jackson to prison for armed robbery. It was three years before a lab mistake was noticed, and the Nevada man was freed as an innocent man.
Deoxyribonucleic acid is a coded molecule providing a genetic map for the development of all known living organisms. By 2000 all 50 states and the federal government required DNA collection from convicted offenders, and was soon expanded by many jurisdiction to criminal arrests.
The number of offender profiles in federal Combined DNA Index System (CODIS) is now about 10 million, with more than a million profiles of people who have been arrested.
Congress in December passed the Katie Sepich Enhanced DNA Collection Act, a grant program to help states pay for the expanded system. Jayann Sepich personally lobbied lawmakers for months to ensure passage.
President Barack Obama signed the bill last month, saying it was the right thing to do.
"In my home state of New Mexico we've had 406 cases solved since we started taking arrestee DNA January 1, 2007," said Sepich. "And that's in a state with a population of only two million people."
The first swab taken of an arrested person an hour after the law took effect produced a "hit" on an unsolved double murder.
Sepich's message is simple. "This saves lives," she said, holding a picture of her daughter. As a crime victim, "We know what it's like, and we don't ever want anyone else to ever know."