India, Feb. 24 -- The masked man who was seen in surveillance photos and videos amid the search for Nancy Guthrie appears to have been at the 84-year-old's front door earlier than February 1, the night cops believe she was abducted, sources familiar with the investigation told ABC News. The sources added that one of the images released by the FBI, showing the person at Nancy's front door without a backpack, was captured by her Nest doorbell camera on a day before her suspected kidnapping.

The FBI said that the photos of the man with the backpack on are from "the morning of her disappearance," Sunday, February 1. This is the day Nancy failed to show up to watch a virtual church service.

The sources said that according to one of the theor...