Last month, the U.S. Supreme Court heard arguments in a case that challenges the constitutionality of collecting DNA samples from individuals charged with a crime.

Justice Samuel A. Alito Jr. described the case of Maryland v. King, No. 12-207, as "perhaps the most important criminal procedure case that this court has heard in decades."

Proponents of the law — and there are many — contend there is no difference between DNA testing and fingerprinting. Twenty-eight states and the federal government have enacted laws that provide for automatic DNA collection from people at the time of their arrest. All 50 states and the federal government collect DNA from convicted criminals.

Last year, the Pennsylvania General Assembly took up Senate Bill 775, which would have required DNA samples from individuals upon arrest for certain crimes.

The bill would have required law enforcement to obtain DNA samples as part of an arrest, similar to fingerprinting. The sample would be entered in Pennsylvania’s DNA database, as well as the federal database. If the person were acquitted, the state would be required to remove the sample from its database.

Interestingly, although 49 states and the federal government joined with Maryland in advocating for the constitutionality of post-arrest DNA collection, the Pennsylvania State Police said, with consternation, that SB 775 would have an enormous impact on the state’s DNA lab. The bill stalled in the state House of Representatives.

Collecting a DNA sample from an arrestee — often called a "DNA fingerprint" — provides a record of the number of times specific sequences of genetic material repeat themselves at 13 locations on the DNA molecule. That string of numbers, according to the United States’ amicus brief, "is a powerful tool for identification because of the infinitesimal likelihood (less than one in 10 billion) that two individuals who are not identical twins will share the same number of copies of the same material at all 13 loci."

The FBI has a coordinated system of federal, state and local DNA databases known as CODIS — Combined DNA Index System. CODIS has more than 10 million DNA profiles.

The case before the Supreme Court grows out of the Maryland arrest of Alonzo King in 2009 on assault charges. Maryland had a state law that permitted police to collect King’s DNA. The sample was submitted to CODIS.

Eventually King’s DNA was found to match DNA recovered during an investigation of the rape of a 53-year-old woman. King was subsequently tried for the rape and sentenced to life in prison.

The conviction was overturned by the Maryland Court of Appeals. The court ruled that authorizing DNA collection from people who have been arrested violated the Fourth Amendment.

In a surprising glimpse into the leanings of the court, conservative Justice Antonin Scalia said to Maryland Chief Deputy Attorney General Katherine Winfree, after she touted the successful prosecutions in her state that flowed from post-arrest DNA collections, "Well, that’s really good. I’ll bet you if you conducted a lot of unreasonable searches and seizures, you’d get more convictions, too."

King’s lawyer, Kannon K. Shanmugam, told the justices there’s a "legitimate expectation of privacy" in the contents of an individual’s DNA.

"An individual’s DNA contains far more information and far more personal information than an individual’s fingerprints," Shanmugam said.

He went on to argue, "The better view is that fingerprinting is not a search, and to the extent that this court has addressed the question it has suggested that fingerprinting is not a search because an individual has no expectation of privacy in their fingerprints because their fingers are constantly exposed."

Some are concerned that after collecting DNA, the government might choose to profile a suspect’s entire genome, looking for a predisposition to violence that could be used to deny a person bail or increase the length of a sentence.

That is not so farfetched. The New York Times recently reported that researchers intend to study the DNA of the Newtown, Conn., school shooter, Adam Lanza. According to the Times, scientists "could look at all of Mr. Lanza’s genes, searching for something unusual like gene duplications or deletions or unexpected mutations … in an extended search for aberrations that could determine which genes are active and how active they are."

Some scientists are skeptical.

"It is almost inconceivable that there is a common genetic factor" to be found in mass murderers, Dr. Robert C. Green, a geneticist and neurologist at Harvard Medical School, told the Times. "I think it says more about us that we wish there was something like this. We wish there was an explanation."

Shanmugam noted during his argument, as described by National Public Radio’s Nina Totenberg, that a complete DNA analysis can reveal a "treasure trove" of information about an individual’s medical and personal history. Allowing the state to have access to the information, without a warrant or some individualized suspicion, he argued, is like loading an information gun to invade people’s privacy.

Should we protect criminals who leave their DNA at a crime scene under the premise that authorities may someday use their DNA for more than matching, maybe even profiling the accused for future dangerousness?

Future dangerousness is already considered in a number of settings. Pennsylvania’s sentencing guidelines, as they currently exist, are a crude form of risk assessment — prior record is the best indicator of future criminal conduct. Counties use risk assessments for bail determinations; the parole board uses risk assessment to make parole decisions.

Pennsylvania will soon incorporate risk assessment into the sentence guidelines. Forecasting future dangerousness has already found a place in the criminal justice system.

Scalia’s left-leaning concerns aside, it appears that a national consensus exists in favor of DNA collection at the time of arrest. For, as Alito noted, "This is what is at stake: Lots of murders, lots of rapes that can be solved using this new technology that involves a very minimal intrusion on personal privacy." •

Matthew T. Mangino is of counsel with Luxenberg, Garbett, Kelly & George P.C. He is the former district attorney for Lawrence County and former member of the Pennsylvania Board of Probation and Parole. You can read his blog, The Cautionary Instruction, every Friday at www.post-gazette.com. You can reach him at www.mattmangino.com and follow him on Twitter@MatthewTMangino.