India, Feb. 5 -- Sheriff Chris Nanos, the elected head of the Pima County Sheriff's Department, is heading the high-profile investigation into the disappearance of 84-year-old Nancy Guthrie, mother of "Today" show host Savannah Guthrie.

Nancy Guthrie's disappearance is now being treated as a potential abduction and is being investigated with support from the FBI. Nancy disappeared from her home in Tucson last weekend.

Chris Nanos began his law enforcement career in 1976 with the El Paso Police Department. In 1984, he joined the Pima County Sheriff's Department (PCSD) as a corrections officer and a year later was promoted to deputy.

According to the Pima County Sheriff's Organisation page, Nanos has accumulated extensive experience in v...