Even as the U.S Supreme Court reviews Maryland's law on police collection of DNA samples, many law enforcement agencies in the state are collecting and holding genetic material from murder victims and people never convicted of crimes.
The practices have raised concerns among some legislators and the public defender's office, who fought for privacy protections and other restrictions in a 2009 state law that allows DNA collection from people arrested on suspicion of serious crimes.
Now, those critics say, police are taking advantage of loopholes and using the genetic material in ways not contemplated by state law. The objections have emerged at a crucial moment for the law, which is up for renewal in Annapolis this year and was argued this week before the nation's highest court.
Law enforcement officials say that everything in the state database of more than 110,000 DNA samples is there legally, and argue that not all samples are covered by the same law that governs collection upon arrest. For example, some are taken based on warrants issued by judges.
But Stephen Mercer, the forensics chief at the public defender's office, said that the theory police are using to keep the samples — that they were originally lawfully obtained — opens up the potential for a wide range of abuses.
"Where do you draw the line? Where do you stop?" he said, describing scenarios in which police pick up and analyze genetic material from cigarette butts and drinking cups. "If you buy into this rationale that 'we're in lawful possession of it,' you can go anywhere."
The case now before the Supreme Court will decide the constitutionality of Maryland's widely used program to take DNA from people arrested — but not yet convicted — on suspicion of violent crimes and burglaries. The case is likely to affect similar programs that have sprouted up in recent years in 27 other states.
But police have been collecting DNA in various forms since it first became available as a law-enforcement tool.
Before 2009, the only way for investigators to get genetic information from the subject of an investigation was to either secure a warrant or get the suspect to submit it voluntarily. When Gov. Martin O'Malley proposed a year earlier to allow collection upon arrest, it touched off a political battle in the General Assembly over privacy and racial profiling.
To allay concerns, proponents of the law agreed to protections — including a provision that requires that suspects' DNA be thrown out if they are acquitted or their cases are dropped.
Police say the restrictions do not extend to collections taken using warrants, and with the law back before lawmakers, members of the Legislative Black Caucus and others are pushing for more privacy safeguards in those and other cases.
Police in Baltimore City have kept DNA from homicide victims, for example, according to a technical manual the agency provided to the public defender's office under a public records request. And police in Montgomery, Prince George's and Anne Arundel counties all confirmed that they do the same.
William Alexander, a spokesman for the Prince George's County Police Department, said samples from homicide victims are used as part of the murder investigation. And Ray Wickenheiser, the director of the Montgomery County Police Crime Lab, said they can be used to solve missing persons cases.
"To me, that's a responsible use of that index," he said.
O'Malley is urging lawmakers to renew the 2009 law without adding any additional restrictions. Raquel Guillory, a spokeswoman, said the different types of collection are separate issues.
"They are two distinct different policies and procedures, one that is lawful and has been in existence and didn't have to do with the folks that are charged," she said. "The suspect database existed way before any of us were here, and it was only after a judge signed a warrant."
Del. Jill P. Carter, a Baltimore Democrat and member of the Black Caucus, said she will push for changes and said lawmakers may not have known all of the ways police could use DNA when they passed the bill.
She pointed to the case of Earl Whittley Davis, who was linked to a Prince George's County murder after police there analyzed bloody clothing taken when he was the victim of an earlier shooting in Howard County.
"It's an example of something that we didn't anticipate," she said.
The Davis case reached the U.S. 4th Circuit Court of Appeals, and last year the judges ruled that his DNA had been unconstitutionally stored in Prince George's County's local database. But the conviction was allowed to stand because the judges decided that police had made a series of honest mistakes.