Role of DNA analysis in solving crimes

(KARE 11) Authorities say DNA analysis helped them link Daniel Heinrich to a sexual assault case from Cold Spring back in January 1989.

The incident happened nine months before Jacob Wetterling's abduction. Thursday, authorities named Heinrich as a person of interest in Wetterling's case.

Heinrich, 52, of Annandale was arrested Wednesday and is now charged with five counts of possessing and receiving child pornography.

"As a result of the development of forensic technology, which did not exist at the time the evidence was collected, Danny Heinrich was determined to be the contributor of DNA on the clothing of the victim of the Cold Spring sexual assault," said Richard Thornton, FBI Special Agent in Charge of Minneapolis.

KARE 11 spoke with that victim, a man named Jared Scheierl, back in 2004 about what happened that night. At that time the 12-year-old Scheierl, who looked quite similar to Jacob, was grabbed off the street by Rocori Middle School, forced into a car and driven to a remote area where he was violently sexually assaulted. Following the assault, he was dropped off and told that if he turned around he would be shot.

DNA profiling started in the eighties. According to Jill Oliveira, public information officer for the Minnesota Bureau of Criminal Apprehension (BCA), the BCA began testing nuclear DNA in 1990.

"Nuclear DNA is inherited from both parents and is unique to an individual, with the exception of identical twins. This type of DNA testing is widely used in forensic laboratories across the country. All cells except red blood cells contain a small amount of nuclear DNA," Oliveira said, in an email.

"This office has been one of the leaders in using DNA to try and find out the truth," said Hennepin County Attorney Mike Freeman.

Freeman said they did the first cold hit case in the country using DNA.

"Subsequently, an individual matched up; we went and found that individual," Freeman said.

Over the years as testing technology advances, nuclear DNA is being obtained from dramatically smaller samples.

"It used to be that you had to have quite a bit of DNA. And to be fair, you had to take raw DNA and give it to the defense attorney and let him do his own study. Now we can take a very small amount of DNA and we can reproduce it," Freeman said.

In a criminal complaint against Heinrich, authorities say, "The predominant profile match to defendant's DNA would not be expected to occur more than once among unrelated individuals in the world population."

Freeman added, "If you really think about it, what your neck leaves on the collar of your shirt is enough to identify you. That's kind of amazing science."

The Combined DNA Index System (CODIS), a national database, provides DNA profiles of convicted offenders. Minnesota Statute 609.117 requires all felony offenders to provide a biological specimen for the purpose of DNA analysis. Currently, the BCA has more than 120,000 convicted offenders in CODIS.