TUCSON, Ariz. — The Pima County Sheriff's Department released a pair of ransom notes Friday in the hope that someone can identify the author due to similarities between them that indicate they were written by the same person, who authorities said used a "unique linguistic style."

Authorities have not yet confirmed that the notes are authentic, but Guthrie's daughter, "Today" co-host Savannah Guthrie, has said she believes they may be — and investigators haven't ruled them out either.

They were sent on Feb. 2 and Feb. 6.

According to the sheriff's department, the two notes share a "unique linguistic style" and are believed to have been sent by the same person.

The style is so distinct, that someone may be able to recognize the writer, authorities said.

The notes included references to the crime scene that may not have been public at the time they were sent — including details about the location of Guthrie's Apple Watch and the smashed floodlight in her backyard.

Fox News Digital first learned about the watch on the morning of Tuesday, Feb. 3. According to authorities, the note had been sent the day before, on Monday, Feb. 2, indicating the sender knew about it before the information began to seep out into the public sphere.

"He knew about the watch on the floor — almost nobody did," said Jason Pack, a retired FBI negotiator who has been following the case closely. 

However, he added, that shows knowledge of the house, not knowledge specific to Guthrie or proof of life. 

"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," Pack added. "And he writes like someone who spends his day sending business email. Money in the amount of. Payment that will need to be paid by. Wanting to have this completed. That is office language."

The sheriff's department is also formally acknowledging that Nest video from Guthrie’s front steps may show the masked intruder on two separate days. 

But they’re still asking for the public’s help identifying him — asking if anyone in the area has seen someone whose behavior changed, including by becoming nervous or anxious after the video came out on Feb. 10, or if they altered their physically appearance, left town, gave their car a deep clean or showed other uncharacteristic changes in behavior.

Anyone with information is asked to dial 1-800-CALL-FBI or, to remain anonymous, call 520-88-CRIME.

The sum of all rewards in the case is over $1.2 million. The money remains unclaimed as of Friday, a day before the six-month mark since Guthrie's kidnapping.

This is a breaking news story.