A former Colorado investigator suggests that grammatical patterns in ransom notes related to Nancy Guthrie's case could help identify a suspect.

In the case of missing Arizona woman Nancy Guthrie, linguistic patterns in ransom notes could aid investigators in identifying the author.

“We are begging for help. We are desperate. We need someone to come forward,” Savannah Guthrie wrote on Instagram as the investigation into her mother's disappearance reached six months.

Authorities report an increase in tips after releasing ransom notes in the Nancy Guthrie kidnapping. Nancy Guthrie, mother of ...