One of Nancy Guthrie's neighbors is weighing in on the "really strange" circumstances surrounding the 84-year-old's disappearance. "There were a lot of dark vans with blacked out windows," Morgan Brown, who lives "a quarter of a mile up the street" from Nancy, told Us Weekly exclusively. "There were a lot of cop cars there at first, and then it was vans, so I assumed that maybe they came across something." According to Brown, those living in the neighborhood are being told to "look at our Ring cameras to see if anything popped up out of the ordinary." He claimed that authorities are "narrowing it down" to some time between 1 a.m. and 4 a.m. local time on Sunday morning. (Nancy was last seen on Saturday, January 31.) "I don't know how they know that," Brown continued. "My Ring cameras don't face the street, but I went through them and haven't heard that anyone found anything." Michael Loccisano/Getty Images News broke on Sunday, February 1, that NBC anchor Savannah Guthrie's mom, Nancy, went missing in Arizona. Pima County Sheriff Chris Nanos called the situation "very concerning" in a statement on Sunday, noting that the authorities aren't ruling out foul play just yet. Savannah, 54, was absent from the Today show on Monday, February 2. It has been confirmed that she's in Arizona. Brown told Us that both "vans and helicopters" arrived at Nancy's address on Sunday afternoon, adding, "I haven't seen anyone there this morning." "They had a helicopter up looking for her. There are no sidewalks in our neighborhood," Brown added. "You just walk on the street and then there's desert, so [they] thought she walked off into the desert or something, but she walks with a cane, so I can't imagine why she would do that. It's desert-y, scrubby mesquite trees and cactus and rocks everywhere." Police Call Savannah Guthrie's Mom Nancy's Home a 'Crime Scene' Amid Search Brown did make it clear, however, that "a lot of people walk in that neighborhood," just not in the early hours of the morning. "This is the foothills of Tucson," he explained. "If you step two feet off the road, you are basically in the thick of the cactus. It's not gated at all." While the Pima County Sheriff's Office called Nancy a "vulnerable adult" in their missing person's report, they made it clear that she has "no cognitive issues at all." Nancy is "not in good" physical health, per the report. (It has since been revealed that Nancy takes a daily medication, and going more than 24 hours without a dose could be "fatal.") Courtesy of Savannah Guthrie/ Instagram "There are quite a bit of retirees and people who have lived in the neighborhood for a while," Brown continued. "You don't hear of a lot of weird stuff in the neighborhood." In a second press conference on Monday, authorities said it's likely Nancy "didn't leave on her own," noting that she "couldn't walk 50 yards by herself." The sheriff referred to Nancy's home as a crime scene and explained that the situation is no longer considered "a search mission." "I can't imagine what someone would want with an 84-year-old woman," Brown told Us. "The thought comes to my mind is maybe they are trying to get to Savannah somehow, political or whatnot. It's horrible news."