Nancy Guthrie ransom notes contain repeated writing quirks that could help identify suspect, expert says

A pair of messages that may have been sent by someone with knowledge of Nancy Guthrie's suspected kidnapping from her Arizona home contain a series of clues about their author, according to retired Colorado investigator Lisa Miller, who said grammatical habits and sentence patterns suggest both notes were likely written by the same person — and could ultimately trigger the tip detectives have been waiting for.

Guthrie is the 84-year-old mother of "Today" co-host Savannah Guthrie.

Authorities have said she was taken from her home in northern Tucson in the early hours of Feb.

1, after a masked intruder appeared on her front steps in recovered doorbell camera video.

Making them public last month could do more than jog someone's memory, Miller said.

It could also put pressure on whoever wrote the notes, potentially prompting a misstep that exposes the author to someone in their own circle.

"The bad guys can't help but look over their shoulder and wonder, are they onto me? Are they coming? And that pressure creates behavioral leakage that we're looking for and people around them might see." NANCY GUTHRIE RANSOM NOTES RELEASE FOLLOWS UNABOMBER ‘PRECEDENT' THAT CRACKED CASE, EXPERT SAYS But the notes themselves may give the public something specific to look for.

"Think about if you've heard someone in your group, maybe outside your orbit that you just encounter that uses this strange language, or if you're written a letter," Miller said.

"If you see something in their writing or in an email where they're using these comma splicings, those are the things that are useful to ask people to look for." The comma splices — where two sentences are joined with a comma rather than separated by a period — are a signature detail in both notes, she added.

"We see it also again in the second note," she said.

"So it's continuous between the two notes, which is one of the reasons why I believe this continuity more likely than not indicates this one author." NANCY GUTHRIE RANSOM DEMANDS RELEASED BY PIMA COUNTY SHERIFF'S DEPARTMENT IN BID TO IDENTIFY SENDER The Pima County Sheriff's Department released the notes in July, six months after Guthrie's suspected abduction from her home in Tucson, Arizona.

Her whereabouts remain unknown, and authorities said they are hoping that someone recognizes the sender's "unique linguistic style." "These are characteristics, these are things that law enforcement can use to ask people, crowdsource for help in this case," Miller said.

And the comma splices aren't the only habits that caught her attention.

"We're seeing also some open compounds through the notes," she said.