(NEW YORK) -- No suspect or person of interest has been identified in the apparent abduction of Nancy Guthrie, mom of "Today" show host Savannah Guthrie, the sheriff's department said on Wednesday.
Nancy Guthrie was last seen at her Tucson, Arizona, home on Saturday night, according to the Pima County Sheriff's Department.
Investigators do not believe Nancy Guthrie left her home willingly and said it appears she was abducted in her sleep early Sunday morning, the Pima County Sheriff's Department told ABC News.
Her family reported her missing on Sunday around noon local time, authorities said.
"We don't know where she is," Pima County Sheriff Chris Nanos said told reporters on Tuesday.
"We do believe that Nancy was taken from her home against her will, and that's where we're at," he said.
The sheriff's department said Tuesday it is reviewing possible ransom notes as part of the investigation. ABC Tucson affiliate KGUN said it received one of the letters, which it forwarded to law enforcement. Officials say they are investigating if any of these letters are legitimate.
Nancy Guthrie's home is considered a crime scene, Nanos said.
DNA samples collected from her home have been confirmed to belong to her, though authorities have not yet confirmed if they were blood, the sheriff's department said Tuesday. There has been nothing to indicate any suspects from the samples taken from the home so far, Nanos said.
It is unknown if Nancy Guthrie was targeted or if this was random, Nanos said.
"We don't know," he said. "We're going to assume both sides of that."
Nanos said Tuesday investigators were waiting to get surveillance footage from the home's security cameras from the companies that own them.
"We've asked them. They know the urgency here," Nanos said.
Investigators are also looking into a camera that was missing from the front of the house, he said.
Authorities said they have Nancy Guthrie's cell phone. Sources briefed on the probe told ABC News that investigators are focusing on Nancy Guthrie's electronic devices to see if there is data that could point to an assailant or a specific time when the abduction would have occurred.
Investigators who processed her home on Sunday "saw some things at the home that were concerning to us," Nanos previously said.
Investigators are also paying attention to the condition of the home and whether things were moved or left out of place, which could suggest that someone with greater strength or agility was in the home and when, sources said.
The FBI, which is helping in the investigation, urged people to submit tips.
"We are looking at this from every angle, but we need your help," Jon Edwards, assistant special agent in charge of the FBI's office in Tucson, said during Tuesday's briefing. "Every lead and tip is important. We are aggressively pursuing and looking into every single one."
"Please help us bring Nancy Guthrie home," he added.
Nancy Guthrie is described as having some physical ailments and limited mobility, but does not have cognitive issues, according to the sheriff. She takes medication that if she doesn't have in 24 hours, "it could be fatal," Nanos said.
In an Instagram post on Monday night, Savannah Guthrie asked her followers for prayers amid the investigation.
"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. raise your prayers with us and believe with us that she will be lifted by them in this very moment," the talk show host wrote.
President Donald Trump said on Tuesday that the situation is "terrible" and said he would call Savannah Guthrie.
Anyone with information is urged to call 911 or the Pima County Sheriff's Department at 520-351-4900.