Article continues below advertisementNeighbors of missing 84-year-old Nancy Guthrie, mother of Today show co-host Savannah Guthrie, reported suspicious activity and dog barking on January 11 and January 31 - two days investigators have been focusing on of late - leading up to her baffling disappearance from her Tucson, Ariz., home.These reports, along with security footage of a suspicious man, might be important to crack the case. Neighbors reported a dog barking and a suspicious vehicle, with investigators analyzing footage from Ring cameras.