There are still a lot of questions surrounding the mysterious disappearance of Nancy Guthrie, the mother of Today show co-host Savannah Guthrie.Pima County Sheriff Chris Nanos said Tuesday investigators believe the 84-year-old w as taken from her Tucson-area home against her will, though he did not disclose what evidence led him to that belief. He noted that investigators have not determined whether she was specifically targeted or abducted at random.According to Nanos, Nancy Guthrie was dropped off at her home around 9:30 p.m. Saturday. She was reported missing about 11 a.m. Sunday, after she did not show up for church. The FBI is providing investigative support, including assistance with analyzing cellphone data and nearby cell towers.Authorities have also collected DNA samples from Guthries home, but so far they have not yielded information that could help identify a suspect, Nanos said.Nancy Guthrie is described as 5 feet 5 inches tall, weighing about 150 pounds, with brown hair and blue eyes.Nanos noted that Nancy Guthrie has trouble getting around, making it unlikely she wandered off. He also noted she does not have any mental issues. However, there is also worry about her health because of the medication she takes. Nanos said it could be fatal if she doesn't receive it.In her first public statement since her mother was reported missing, Savannah Guthrie thanked supporters for their prayers."Thank you for lifting your prayers with ours for our beloved mom, our dearest Nancy, a woman of deep conviction, a good and faithful servant," Guthrie said. "Raise your prayers with us and believe with us that she will be lifted by them in this very moment." ...read more read less