Authorities have seen an increase in tips after releasing the ransom notes that were sent to Nancy Guthrie's family.
Authorities have not confirmed the ransom notes are authentic, but their release has generated a "slight" uptick in tips, a spokeswoman for the Pima County Sheriff's Office said. The office released the full content of the alleged notes on July 31.
"Nancy Guthrie Task Force investigators have seen a slight increase in tips since the two ransom notes were released last week," Pima County Sheriff's Office Public Information Officer Angelica Carrillo told Fox News Digital. "All tips have been followed up on."
NANCY GUTHRIE RANSOM DEMANDS RELEASED BY PIMA COUNTY SHERIFF'S DEPARTMENT IN BID TO IDENTIFY SENDER
The alleged ransom notes were sent on Feb. 2 and Feb. 6.
"Hello Savannah," one of the notes read. "We have your mother Nancy. She is safe but scared. She will be held for ransom and once payment is received she will be released unharmed."
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"She had a white smart watch on the floor of the foot of her bed and the white flood light in backyard was destroyed," it continued.
In a follow-up message sent to the Guthrie family, the alleged ransom notes states that Nancy Guthrie has passed away.
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"We did not fully grasp the seriousness of her physical condition. We never intended to hurt her, that was not our intention. She perished shortly after she was taken. We believe it was heart related," the purported ransom note states.
As previously noted, Fox News Digital has not independently verified the authenticity of the notes or their contents.
Fox News Digital learned of the watch on the morning of Tuesday, Feb. 3, a day after the note was sent, according to authorities. That timeline suggests the sender knew about the watch before the detail became public.
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Jason Pack, a retired FBI negotiator, said the watch detail demonstrates familiarity with the house but not necessarily knowledge unique to Guthrie or proof that she was alive.
"He knew about the watch on the floor — almost nobody did," Pack said. "In my view, two things the language does support: He writes like a native English speaker. The idiom and the small connecting words are all in the right places, and at this length that is hard to fake."
Anyone with information is asked to call 1-800-CALL-FBI, or 520-88-CRIME to remain anonymous.
