Hoping to solve and prevent more crimes, the federal government and a growing number of states are casting the DNA net wider by taking genetic samples from people accused but not convicted of breaking the law.

Civil liberties advocates say the practice makes a mockery of "innocent until proven guilty" and could overwhelm already-backlogged crime labs.

All states take DNA from convicted criminals and enter it into databases for use in solving crimes. But this spring, Kansas and New Mexico passed laws to start testing those only arrested for crimes, joining California, Louisiana, Minnesota, Texas and Virginia.

And last year, Congress said it was OK to take DNA from those arrested for federal offenses — felonies and misdemeanors alike — and foreigners who are being detained, whether they have been charged or not.

"At first, this bothered me that we were undermining criminals' civil rights — you are innocent until proven guilty," said Tennessee state Sen. Ron Ramsey. But "if you're talking about murder, assault and things of that nature, law enforcement will tell you that lots of times the perpetrator has done this before. If it does solve the crime, I'll go along with that."

Ramsey, a Republican, wants to expand testing to those arrested for burglary and serious violent crimes such as murder, rape or kidnapping.

The new laws let states take genetic samples upon arrest and often before formal charges are brought. None of the state laws allow testing of people arrested for minor crimes.

In California, the law — which passed by voter initiative in 2004 but will not take full effect until 2009 — requires that anyone arrested for investigation of a felony must give a DNA sample. California is phasing the measure in, starting with those accused of murder, voluntary manslaughter or felony sex crimes.

The federal legislation passed with little debate as part of a larger criminal justice measure.

Many of the laws have yet to be put into practice. Kansas's new law begins Jan. 1 and will initially require that DNA be collected from any adult arrested or juvenile taken into custody for a violent felony, such as murder or rape. Starting in 2008, samples will be taken in all felony cases.

Laws in all states but Kansas allow for the DNA record to be removed if the accused is not convicted, usually upon the request of the person tested, according to Lisa Hurst, who tracks DNA legislation for the law firm Smith Alling Lane in Washington.

But critics argue that databases could end up containing the names of people who were found innocent.

"This is absolutely a line that should not be crossed. You are talking about suddenly changing the very nature of the databases," said Tania Simoncelli with the American Civil Liberties Union.

She said the ACLU is considering a legal challenge.

At the Innocence Project, a group that has relied on DNA to free the wrongfully convicted, Barry Scheck warned that the labs that will have to analyze the monumental number of samples could become too swamped to quickly process DNA lifted from crime scenes.

Ramsey predicted the argument for expanded testing will get a sympathetic ear from lawmakers. He noted that fingerprints are routinely taken upon arrest. And "DNA is the fingerprint of the 21st century."