Article continues below advertisementAn expert detective is weighing in on the new ransom notes demanding one Bitcoin to deliver Nancy Guthrie's kidnappers "on a silver platter."On Monday, April 6, TMZ reported they received two more emails from the same sender, one of which claimed to know the location of Guthrie's body. The second letter alleged they had seen the 84-year-old alive in Mexico at one point.Brian Martin, a cold case detective, told NewsNation investigative reporter Brian Entin on Tuesday, April 7, that whoever sent the notes was presumably someone who "wants to be heard.