Here's what happened each day of the Nancy Guthrie disappearance

Federal investigators have released new surveillance video showing a masked and apparently armed person on Nancy Guthrie’s doorstep the night she went missing. Tuesday's announcement was the first major development in the search for the mother of “Today” show host Savannah Guthrie. Authorities have not identified any suspects and are seeking help identifying the person in the video. It's been more than a week since 84-year-old Nancy Guthrie was apparently abducted from her Arizona home. Her children have made emotional pleas for help, and the case has drawn national attention. Two deadlines in purported ransom notes have passed without resolution.