The search for US Today tv show anchor Savannah Guthrie’s mother Nancy is still underway after 100 days since kidnapping from her Arizona home on February 1.

According to Pima County Sheriff Chris Nanos, the department is still investigating blood evidence and DNA found at the crime scene. Speaking to People, the officials said that the key to solving Nancy’s kidnapping case lies in interpreting DNA-based evidence.

Earlier in an interview with 12 News, Chris Nanos shed light on ongoing investigatory efforts.

“We continue to work with our labs, whether it’s on the digital end or the biological end: DNA. It moves at a snail’s pace, I guess, for some. But for my investigative team, and for me, we look at this as, no, this is doing exactly what we need it to do.”

Along with investigation, various theories related to evidence in Nancy have surfaced throughout the period of four months.

The retired FBI Agent has come up with another new theory involving DNA found at the home of Nancy.

In an interview with NewsNation correspondent Brian Entin, Steven Moore cast doubt on the investigators’ claims that only a single hair was recovered from the 84-year-old home.

Moore argued that if investigators can find one hair, there must be “probably 10 more” but they have been either neglected or undiscovered.

Emphasizing that much of the physical evidence in cases like Nancy’s is “invisible” to the naked eye. But when it comes to forensics, they have been trained enough to locate such hard-to-find trace materials.

Earlier this week, Sheriff Nanos also remarked that, “I believe, at some point in time, we will make an arrest in this case.”

But Moore also challenged Nanos’ “we are getting closer” in the case remark, highlighting the backlash the department is facing due to delays in discovering major breakthroughs.

Nanos finds himself at the center of a growing firestorm. Public confidence has declined as critics voice sharp complaints over his controversial oversight of Nancy's case.