New Delhi, Aug. 18 -- Two messages believed to be linked to the suspected kidnapping of Nancy Guthrie may contain clues about who wrote them, a retired Colorado investigator Lisa Miller told Fox News. She said similarities in grammar, sentence construction, and word choices suggest both notes were probably written by the same person.

Guthrie, 84, is the mother of "Today" co-host Savannah Guthrie. She was taken from her home in northern Tucson in the early hours of February 1 after a masked person was captured on doorbell camera footage outside the property.

Miller said the public release of the messages could help investigators by encouraging people to recognise the writer's unusual language patterns. She suggested that someone who know...