Nancy Guthrie’s investigation: Why the road is frozen.

There was absolutely no reason to leave the crime scene, said Joseph Giacalone, a retired NYPD sergeant, assistant professor at John Jay College of Criminal Justice and author of a textbook on criminal investigation.

“That whole house, that property should have been fenced off. No one should have set foot in that place except for law enforcement and just to do the investigation.”

Even if there are future arrests, he said, the crime scene issues mean “everything is going to be questioned” by the defense.

Mishandling a crime scene can greatly reduce the chances of solving the case, he added.

Sheriff Nanos alternately denied and admitted wrongdoing. At a press conference on February 5, he said he would have kept the crime scene longer if given another chance.

“I probably could have avoided that,” he said, adding, “We got what we thought was done.”

But Nanos has been plagued not only by criticism of the Guthrie case, but throughout the investigation. According to documents obtained by the Arizona Republic, local media have scrutinized his past — he received a written reprimand in El Paso.

When contacted on the broadcast, Nanos responded on March 9: “Is this your ‘urgent’ question? Are you sure you don’t want to go back to my high school and ask why I got swats from the principal? Good luck with your hit piece.”

The next month, the Pima County Board of Supervisors requested answers from the sheriff, who filed written responses through his attorney, Arizona media reported. The board later voted not to remove him, but Supervisor Rex Scott said the sheriff needed to address his lack of confidence in his leadership.

As investigators soldiered on, the global interest in the case and the celebrity of Guthrie’s daughter probably didn’t help the case, experts said.

“The celebrity probably realized there was a big manhunt and drove the kidnapper underground,” said PI Ribacoff, who speculated that Guthrie may have died early so the suspects could dispose of her body.

Other theories differ. Smith, meanwhile, is suspicious of the authenticity of the ransom notes — and believes Guthrie was taken to Mexico so she could simply disappear.

Nanos, for his part, told BBC News that he was confident Guthrie would eventually be there, even if it took “10 days, 10 months or more”. Nearly 40,000 tips came in as of February, and the sheriff has remained committed to solving the crime ever since.

And the eyes of the world remain glued to the case – but international sympathies remain with the Guthrie family. They offered a $1 million reward and pleaded for tips.

Savannah Guthrie renewed her appeal during a tearful segment on her NBC morning show after the list of the two memorabilia was revealed this week.

“I want to take this opportunity to ask people, really beg people, to come forward,” she said. “Someone knows something.”