India, May 14 -- Chris Nanos, the sheriff leading the investigation into Nancy Guthrie's disappearance, recently said that investigators almost immediately suspected something more serious than a routine missing persons case when the first call was made. Speaking to PEOPLE as the case crossed the 100-day mark, Nanos further recalled receiving an alert on February 1 about an 84-year-old woman missing from her home in Tucson.

According to Nanos, the situation escalated within minutes.

"A few minutes after the chief notified him about an 84-year-old woman missing from her house," Nanos said, he received another message stating the scene "doesn't look right, something is wrong. We're calling homicide."

Nanos explained that homicide detecti...