A timeline of Nancy Guthrie's disappearance as search stretches on

As the search for Nancy Guthrie, the 84-year-old mother of "Today" show co-host Savannah Guthrie , stretches on, investigators are still seeking tips that could help break the case and lead to her return. The FBI and sheriff's department obtained video of an apparent suspect, who is described as a man of average build with an approximate height of 5-foot-9 or 5-foot-10. In the Nest doorbell camera video taken at Nancy Guthrie's home, he was wearing a face mask, gloves and a black Ozark Trail Hiker Pack backpack, the FBI said. Guthrie was reported missing on Sunday, Feb.1, after not showing up for church, and the sheriff said it appeared she was abducted from her home in Tucson, Arizona. Her family has been pleading for her return, and the sheriff says they have been cleared of any involvement. Savannah Guthrie and her two siblings have appealed directly to whoever may have taken their mother. The FBI said it was taking two emails seriously, including what appeared to be a ransom note with a demand for payment in bitcoin. Here is a timeline of Nancy Guthrie's disappearance and the investigation. Jan. 31: Nancy Guthrie last seen Nancy Guthrie was last seen on Saturday night, Jan. 31, authorities said. She arrived at her daughter Annie's home at 5:32 p.m. She dined there and was dropped off at her own home after dinner at around 9:48 p.m. She was dropped off at home by her son-in-law, Tommaso Cioni. Police say he waited until Nancy Guthrie was inside before driving off. …