India, Feb. 2 -- Homicide investigators have called in amid the urgent search for NBC's Today show host Savannah Guthrie's mother, who was reported missing on Saturday night.

Nancy Guthrie, 84, went missing between 9:30 pm and 9:45 pm from her residence in the Catalina Foothills, located just outside Tucson, Arizona.

Pima County Sheriff Chris Nanos has stated that foul play is still a possibility and that drones, aircraft, and canine units, provided by Customs and Border Protection, are being used in the search efforts.

During a press conference, he informed reporters that "concerning evidence" had been discovered, which led to the involvement of homicide investigators.

The sheriff's office has indicated that the woman who is missing ...