In their effort to beat the statutes of limitations that prevent people from being charged with a crime after a certain amount of time has passed, prosecutors in some parts of the US are trying a new tactic: They're charging half-eaten food, saliva-crusted glasses or other inanimate objects with the crime.

That's because prosecutors now have DNA evidence as a way to get around statutes of limitations. One way to make sure a criminal doesn't get away by hiding long enough is to simply charge the DNA itself, and wait until the DNA is matched to an actual person.

Laura Bauer of the Kansas City Star reported Monday that prosecutors "in a few pockets of the country" have begun issuing "John Doe" arrest warrants that identify only a person's unique DNA signature. Once the arrest warrant on the DNA is in place, the statute of limitations on the applicable crime will no longer run out. Bauer reports:

Since 2002, Jackson County [Missouri] prosecutors have filed 28 John Doe complaints....

Whenever a burglary, robbery or vandalism with DNA evidence is nearing its statute of limitation, police alert [prosecutor Ted] Hunt’s office, and prosecutors file a no-name charge.

By filing these complaints, and charging the DNA instead of a named suspect, prosecutors put cases on hold until they know whose genetic fingerprint they charged. These cases otherwise wouldn’t be solved within the statute of limitations, and the suspects would be let off scot-free.

But it may be more than "a few pockets of the country" that are trying out this technique. According to the Web site of the district attorney for Denver, Colorado, "John Doe" DNA warrants have been used at least in California, Colorado, Kansas, New York and Wisconsin.

“We may have 2 1/2 years left" on the statue of limitations, Denver District Attorney Mitchell Morrissey told the KC Star. "It doesn’t matter, we file the case. ... We freeze everything in place. … Otherwise, the bad guy gets away.”

Last month, the Supreme Court of California ruled that no-name warrants based on DNA evidence are allowed under state laws. According to Kelly Lowenberg at the Stanford Law School blog, the court ruled that DNA-based warrants are specific enough to be constitutional, and that they do "stop the clock running" on statutes of limitations.

But while this new crime-fighting technique may be useful to prosecutors, it raises questions about the relevance of statutes of limitations on crimes in the age of DNA. Defense attorneys argue that statues of limitations exist for a reason -- if a person is charged with a crime after too long a period, it may be difficult to defend against the charges. "People’s memories fade" and "witnesses move and can’t be found," Bauer reports at the KC Star.

“If a defendant in a property crime is arrested 20 years after the fact, based on his DNA, he’s not able to defend himself effectively,” Kansas City defense attorney J.R. Hobbs told the KC Star.

And the likelihood of the long arm of the law reaching even further grows as DNA databases in the US and around the world expand.

Last year, the FBI announced it would start collecting DNA samples from people who weren't charged with a crime. Thus far, only people charged with an offense had their DNA taken. It's estimated that the FBI's database will grow at a rate of 1.2 million DNA profiles per year from now on, compared to a growth rate of about 80,000 per year prior to the new policy. The FBI already has an estimated 6.7 million DNA profiles on record.

Some civil rights advocates worry about the implications to privacy and personal freedom from a growing reliance among governments on DNA evidence. For instance, in the United Kingdom it was alleged last year that police forces were randomly arresting people simply to get their DNA on to the books. Some accused British police forces of racial profiling in that effort, noting that three-quarters of Britain's black males under the age of 35 are now on the DNA database.

The KC Star's Bauer notes that DNA is now being used in a much wider array of criminal investigations than has been the case in the past. While DNA testing was usually reserved for murder and rape investigations, its easy availability today means it is being used in robbery and even vandalism cases.

Denver police are so aggressive that they worked on a case in which a car window was broken and just $1.40 in coins were stolen.

A drop of blood was found on a car seat. When no match came up in the database, they went even further, checking for near-matches in what’s called a “familial DNA” search.

The name of a convicted felon came up. In the end, the felon’s brother was arrested.