Article continues below advertisementFormer FBI agent Jennifer Coffindaffer is pushing back hard against reports suggesting the investigation into Nancy Guthrie's case has gone "cold."The retired investigator, who spent 28 years in law enforcement, said there's still serious movement behind the scenes in the search for the missing 84-year-old mother of Savannah Guthrie. It has now been more than a month since Nancy vanished on February 1.Article continues below advertisementSource: @savannahguthrie/InstagramJennifer Coffindaffer said Nancy Guthrie's case is not 'cold.