The suspect was wearing a 25-litre Ozark Trail Hiker Pack backpack in the footage, the FBI said.
After the doorbell footage was released, investigators received more than 13,000 tips, including 4,000 in the 24 hours.
The FBI has also increased the reward for information about Guthrie’s disappearance from $50,000 (£36,700) to $100,000.
The county sheriff department said the suspect description “remains a key focus”, adding: “However, investigators are not ruling out any individuals or possibilities.”
Investigators have also issued a wider appeal for video footage from Guthrie’s neighbours.
Police have said Nancy Guthrie, 84, needs daily medication and has limited mobility.
Savannah Guthrie and her two siblings have released a number of social media pleas directed at their mother’s abductor.
They believe she is still alive and have indicated they would be willing to pay for her safe return.