Nancy Guthrie has now been missing for a month.

Police have expanded their search to include new video surveillance of cars in the vicinity of Guthrie's home the night she disappeared. 

Some investigators now say this is the best new search tool. Internet sleuths have also suggested a possible star emblem on the suspect's jacket, seen in door cam footage, and a possible tattoo.

More than 1,500 tips have been called in since Savannah Guthrie announced a reward of up to $ 1 million.

• TIPLINE: FBI TIPLINE PH: 1-800-CALL-FBI (1-800-225-5324)
• ANONYMOUS TIPS: PH: (520) 882-7463

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