California's "Grim Sleeper" serial killer evaded authorities for three decades until last summer.

That's when investigators turned to a controversial new type of DNA analysis -- a technique that merits careful use in Minnesota. Using familial DNA doesn't pinpoint the perpetrator, but it can generate new leads by potentially identifying the criminal's family members.

Lonnie Franklin Jr., a Los Angeles man in his late 50s, is suspected of at least 10 murders and is now awaiting trial. Officials trying to crack the cold case knew that DNA found at crime scenes did not directly match anything in law enforcement criminal databases.

But they did find a partial match -- which can indicate a biological relationship -- with genetic material from Franklin's son, who was in the database because he had a felony weapons conviction.

That led them to scrutinize Franklin. Undercover officers collected DNA from him. Experts then deemed a match from material found at Grim Sleeper crime scenes.

Minnesota law enforcement authorities understandably want to use this valuable investigative technique to solve crimes here, and they should be able to do so -- within certain limits.

Authorities likely don't need a state law to begin using it, but, to their credit, they are calling for a law that not only authorizes the technique's use but puts much-needed restrictions on its use. They also are welcoming the high-profile debate that their push for the law has spurred.

While familial DNA can help solve difficult crimes, its use carries legitimate privacy and civil-rights concerns.

"There has to be a policy debate. If it's not at the Legislature, then we'll have it through the administrative rulemaking process. Not everybody will be at the table," said Hennepin County Sheriff Rich Stanek.

A key question: Are innocent family members punished in some sense if police question them about their kin's potential misdeeds? Or are they merely inconvenienced?

It's a troubling issue, even if those whose DNA is in criminal databases generally have previous crime convictions. There are also a disproportionate number of African-Americans in the national offenders database, according to a 2006 paper in the Journal of Law, Medicine and Ethics. Blacks likely will be answering questions more often about family members than other races will be.

Hank Greely, a law professor at Stanford University and the lead author of the law journal article, said it's not clear how many states use familial DNA, though California and Colorado have been at the forefront.

State Rep. Tony Cornish, R-Good Thunder, has introduced a bill that would authorize it here but also set down important restrictions.

Key components include limiting familial DNA's use to crimes involving first- or second-degree murder or criminal sexual assault, and requiring that all other investigative leads have been exhausted. The requesting officer also must meet other guidelines from the superintendent of the state Bureau of Criminal Apprehension.

Those limits -- California and Colorado also have restrictions -- make sense. Given the concerns about privacy and civil rights, familial DNA should be used only when absolutely necessary. But it should be a tool for law enforcement to use judiciously.

Cornish's bill is a good starting point. Further debate will improve it.

Stanford's Greely said additional safeguards are needed to ensure individuals' confidentiality. Having county attorneys sign off on this technique's use -- a provision that was in the bill at one time -- also should be reconsidered.

Policy parameters for familial DNA analysis should be set down openly and transparently. The Legislature is the right place to debate this crime-solving tool and determine how best to use it.

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