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(KMSP) - A new type of DNA testing led BCA investigators to Danny Heinrich in a child abduction case, which ultimately helped them crack the Jacob Wetterling case.
The recently developed DNA technology that connected Heinrich is called nuclear DNA, which is left behind simply by touching someone, like grabbing an arm.
The standard way to look for DNA is in a search room with overhead lights off.
“Many biological fluids will fluoresce or glow under an alternate light source,” said Catherine Knutson, BCA forensic science director.
Forensic analysts used this method to examine Jared Scheierl's sweatshirt years ago.
“So the first time it came into the laboratory, that's the sort of examination that was done and nothing was observed at that point in time,” said Knutson.
For years, there was no DNA link to Danny Heinrich because they did not find any bodily fluids on the sweatshirt.
In 2012, they found DNA by swabbing the sleeve to pick up skin cells or "touch DNA."
“So if you're looking at, for example, a door handle, you touch a door handle to exit a door or enter a door, you look at that door handle, you're not seeing your DNA that's sitting there and that's essentially what we're testing,” said Knutson.
What makes this possible is a machine that is able to break open the cells and scrub away all the excess, leaving only the nucleus.
They then needed to match the DNA found through the new method to Heinrich. In 2015, they used hair they'd collected during the original investigation.
“As we moved forward, he was not cooperative with investigators,” said Drew Evans, the BCA superintendent. “They tried to talk to him on different occasions throughout the years and he was not cooperative and so, we wanted to be very careful how we obtained a sample from him, a known sample so we would make sure not to tip our hand.”
Evans said they moved very methodically and slowly, knowing they had one shot to get it right and get Heinrich to lead them to Jacob Wetterling.