The FBI has shared the first physical description of the man they believe kidnapped Nancy Guthrie, mother of US news anchor Savannah Guthrie. Nancy, 84, disappeared from her home in Tucson, Arizona, two weeks ago. Authorities think she was taken against her will. Using doorbell camera footage, the FBI says the suspect is a man about 5ft 9in to 5ft 10in tall with an average build. This is the first time the FBI officially named the man in the video as a suspect. After forensic analysis, the FBI identified the suspect's backpack as a 25-litre Ozark Trail Hiker Pack. Black gloves were also found during the search for Nancy, CBS reported. Nancy was last seen on January 31st when family dropped her home. Church members noticed she was missing the next day and alerted her family. Authorities warned she may be in serious danger without her medication. Pima County Sheriff Chris Nanos said Nancy is "not in good physical health" but has no cognitive issues. Since the investigation began on February 1, the FBI has received over 13,000 tips, including 4,000 after the doorbell video release. The FBI doubled the reward to $100,000 for any helpful information. Earlier, a man was detained and his Rio Rico home was searched but he was later released. He told reporters he did not know who Nancy Guthrie was. Nancy's daughter Savannah and her siblings have made heartfelt social media pleas to the kidnappers, believing their mother is still alive. They have also offered to pay for her safe return.