Forensic Twist: A blood trail may have forced the suspect to leave behind critical footprints, according to experts — a detail that could quietly crack the Nancy Guthrie case wide open…

As authorities comb through thousands of tips in the search for Nancy Guthrie, the missing 84-year-old’s home could still be providing leads for investigators to follow. Blood stains on the porch – which officials confirmed are Guthrie’s – suggest ways her kidnapper may have left traces behind, a forensic expert says.

“Blood is very sticky … if she’s leaving that blood stain on the step, I’m sure there was blood inside the house, which is wonderful for footwear,” former police detective Mike McCutcheon told CNN’s Laura Coates.

“You step in that, because you’re dealing with her, you’re in close proximity, you’re leaving those foot impressions behind,” McCutcheon said, noting forensic investigators have methods such as spraying certain chemicals to highlight traces of this type of evidence.

McCutcheon said the blood stains on the porch also give investigators insight into what happened.

“I would not be able to tell you how she was taken, but what I can tell you is that those are drip stains,” McCutcheon said, noting the relatively large size and uniform shape that suggests the blood was “falling at ninety degrees.”

“If it were an impact stain, blood coming off from a weapon … you’re going to have smaller stains and they’re going to have some direction. So there was some altercation that was in there that caused her to bleed, and that we can’t determine.”

Detainment of now-released man “diverted resources” in Guthrie search, former FBI official says

Former FBI Assistant Director: Nancy Guthrie investigators ‘aren’t as far along as I thought they were’

01:33

FBI continues to search for evidence near Nancy Guthrie’s home. Here’s the latest

A member of the FBI surveils the area around Nancy Guthrie's residence on Thursday.

A member of the FBI surveils the area around Nancy Guthrie’s residence on Thursday.
Brandon Bell/Getty Images

FBI agents were seen today scouring the rugged desert terrain surrounding Nancy Guthrie’s Tucson home as the search for the missing 84-year-old woman continues for an 11th day.

“HE’S STILL ALIVE?”  Ten years. A missing boy. A nation that never stopped searching. And now… a jaw-dropping twist that has reopened one of the country’s most haunting mysteries.  DNA evidence from a young man in Western Australia shows a 69.23% genetic match with William Tyrrell’s father, Brendan “Bones” Collins — sending shockwaves across families, investigators, and the public alike.  Could the truth about William’s disappearance have been hiding in plain sight this entire time? Everyone is asking the same chilling question…