A growing number of local police departments are building up DNA databases of residents in their communities, raising new privacy concerns.
The U.S. Supreme Court ruled last week police can take DNA samples without a warrant from suspects arrested for serious crimes.
But The New York Times reports many police departments were already doing that, even with low-level suspects and victims.
Many local police bypass federal and state regulations and log-jams to create their own rules.
Supporters of the idea say it helps them solve crimes since they have quick access to DNA data on local low-level suspects from previous incidents.
But in some cases they hold on to DNA even if suspects have been cleared, or they keep victims' DNA after the crime has been solved.
"That's so profoundly disturbing - that you would give DNA to the police to clear yourself and then once cleared, the police use it to investigate you for other crimes, and retain it indefinitely," Stephen B. Mercer, the top attorney in the forensics division of the Maryland public defender's office, told the Times.
New York City now has a DNA database on 11,000 suspects. Orange County, Calif., has 90,000 DNA profiles.
Some believe the recent Supreme Court ruling could lead to an escalation of DNA gathering on the local and national levels.
One of the four Justices dissenting in that case, Justice Antonin Scalia, warns that the DNA of any individual can now be entered into a national database if that person is ever arrested -- "rightly or wrongly, and for whatever reason."
He says it's a practice that will solve some additional crimes, but the same would be true if DNA were taken from every airplane passenger, or from every child starting public school.