Advances in DNA testing at the heart of Wetterling case developments

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In the wake of new developments announced last week in the 1989 disappearance of Jacob Wetterling, the state's crime fighters explained Monday how advances in DNA testing are helping them solve more cases.

Last week, authorities identified 52-year-old Daniel Heinrich of Annandale as a person of interest in Wetterling's disappearance, and also linked him through DNA evidence to the January 1989 kidnapping and sexual assault of a 12-year-old Cold Spring boy.

Prosecutors say Heinrich’s DNA was found on an article of clothing worn by the victim at the time of the abduction.

Since that news broke, officials at the Bureau of Criminal Apprehension say they've received many requests for more information about DNA testing.

So the agency's director of forensic science services, Catherine Knutson, held a news conference Monday to answer questions, and the BCA released a recording of her comments. (Knutson would not comment on specific cases under investigation, including the Wetterling case.)

Getting more information from less

Knutson said DNA testing procedures used now are much more sensitive than those available in decades past, and can detect DNA from samples that are so small they can't be seen with the naked eye.

 Catherine Knutson (Photo from BCA video)

Catherine Knutson (Photo from BCA video)

"The different types of tests that have been implemented over the past 20 years really had one common goal, and that was to be able to get more information from a smaller piece of evidence," Knutson said.

One example of that is so-called "touch DNA," which can be found on items that have been touched by a suspect, such as a piece of clothing.

"We can target those types of areas and try to see if any DNA was left behind,” she said.

Knutson also noted that hair samples are useful evidence, especially in cold cases, because they don't degrade very quickly.

"There have been a lot of successes testing very aged hairs from old cold cases, and getting useful information from them," she said.

The case against Heinrich

Heinrich was arrested Wednesday on charges of possessing and receiving child pornography. He cannot be charged in the Cold Spring case because the statute of limitations on that crime has run out, officials said.

The Associated Press spoke to the victim in that case, Jared Scheierl, who said he hopes the investigation will finally determine what happened to Wetterling. The two cases are similar, and occurred several months apart.

Police say shoe prints from the place where Jacob was abducted may match Heinrich's. Police hope publicizing their suspicions about Heinrich will encourage people to come forward with information that may help in the investigation.

Wetterlings to speak

In another development in the case, Patti and Jerry Wetterling are scheduled to speak publicly Tuesday for the first time since Heinrich's arrest.

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