Take the backpack that was found shortly after Jessica Ridgeway was reported missing as an example. It was found in a neighborhood in Superior.
"What if some kid sneezed on [Jessica's] backpack during recess [at her school]? Then we're focusing all of our efforts on this, and when we don't find that person we then think we haven't found the killer," Dr. Elizabeth Johnson told 9News from her California home on Monday.
Dr. Johnson has more than 20 years of experience working in the field of DNA technology. She was called by the defense to testify during the Kobe Bryant case in Colorado. She currently works in private forensic consultation.
"I think the biggest misconception about DNA technology is that it is infallible and that there are never mistakes made," she said. "Just because you someone's DNA on an object doesn't make them guilty of a criminal act."
Of course, she said, the presence of particular bodily fluids can also be indicative of a criminal act, and thus lead investigators closer to a killer. But she cautions that CSI-like television shows have raised the expectations of many people in inappropriate ways.
Dr. Andrew Bonham is an assistant professor at Metropolitan State University and says he still believes DNA will help in the Ridgeway murder investigation.
"I am almost 100 percent convinced," the molecular biology expert said. "That (the killer) is going to leave traces of DNA behind and that investigators are going to find those traces."
He said that current technology allows investigators to collect even seemingly miniscule portions of bodily fluids in an effort to identify critical DNA markers.
"We're now talking about almost less than you can perceive," he said.
Dr. Johnson said it's not hard to leave large amounts of DNA behind.
"If you were to lick your finger to turn the page of your notepad, you're going to be putting tens of thousands of cells onto your finger," she said.
(KUSA-TV © 2012 Multimedia Holdings Corporation)