As the search for Savannah Guthrie's missing mom, Nancy Guthrie, approaches its third week, one former sergeant is providing an expert opinion on what could come next. "The best-case scenario is they obviously find her alive," Troy Hillman, retired cold case homicide sergeant with the Phoenix Police Department, exclusively told Us Weekly on Wednesday, February 18. "And they've got the bad guy and everybody can go home and it'll take years to go to trial." One possible way to get answers and bring justice is through DNA. Earlier this week, the Pima County Sheriff's Office confirmed the DNA from a set of gloves found two miles away from Nancy's home in Tucson, Arizona, did not trigger a match in the national CODIS database and did not match DNA found at the property. Savannah Guthrie's Mom Nancy Is Missing in Arizona: Timeline of the Case "They'll swab everybody that's been at the house and in contact, then they'll exclude," explained Hillman, who is not part of the investigation. "And they'll say, 'OK, not their DNA.' But there could be somebody random. Whoever it is, I'm sure they're gonna get a call from the FBI or they're gonna have agents show up at their house and say, 'Why is your DNA inside this house?'" When asked how significant it is that there wasn't a DNA match from the gloves in the CODIS database, Hillman said it just means the person hasn't been convicted of a previous crime. "It's evolved over the years," Hillman - who is the author of Chasing Down the Zombie Hunter - explained to Us. "There are a lot of rules surrounding what goes into CODIS and not. That just tells me that he's not committed any or been convicted of a felony." Nancy and Savannah Guthrie Courtesy of NBC News Nancy was last seen alive in Tucson, Arizona, on January 31 after enjoying dinner with family members. Police later confirmed a 911 call was made on February 1 after the 84-year-old didn't meet up with friends to watch a church service virtually. On February 10, FBI Director Kash Patel shared surveillance photos taken on Nancy's porch the night of her disappearance. The images appear to show a possible suspect wearing a ski mask and a backpack while attempting to cover a camera on the property. Police, however, have yet to officially identify a suspect or person of interest. "To me, it's one of the most bizarre missing persons investigations I've ever seen," Hillman shared with Us before predicting how investigators are feeling. "They want to get this bad guy. They want to get Nancy home." Nancy and Savannah Guthrie Courtesy of NBC News On February 15, Savannah returned to Instagram and shared an emotional plea to whoever is responsible for Nancy's disappearance. "I just wanted to come on and say that we still have hope," the Today coanchor shared. "We still believe, and I wanted to say to whoever has her, or knows where she is, that it's never too late and you're not lost or alone. It is never too late to do the right thing and we are here. We believe. We believe in the essential goodness [of] every human being, and it's never too late." Savannah Guthrie's Mom Nancy Guthrie Is Missing in Arizona: What to Know As Americans continue to be captivated by the case, Hillman believes many investigators working the case have likely built a connection to the Guthrie family as well. "We're human beings, and we're ultimately tied to the family," he said. "We want to get her back and not screw up the investigation." Anyone with information on Nancy's disappearance is urged to contact 1-800-CALL-FBI or visit http://tips.fbi.gov.