Transcript for Possible new sighting of missing teacher and former student

A lot coming up there. Now the latest on that teacher who ran away with a former student. A photo was released overnight in Nebraska. Eva pilgrim has details. Reporter: Today marks three weeks since these two disappeared. For much of that time nothing. Not a clue but now at least one confirmed sighting giving her family some hope. This morning, Nebraska police posting this surveillance cam photo of what they say could be tad Cummins with 15-year-old Elizabeth Thomas at the McDonald's this past Sunday. While they haven't been able to possley identify them yet, this new video of the pair in Oklahoma gives fresh clues in the three-week search for the Tennessee teen and her alleged kidnapper. It was good to be able to see her face again. Reporter: Tad Cummins and Elizabeth Thomas captured on security cameras at a Walmart in Oklahoma City two days after her disappearance. Nearly 700 miles away from her home in Columbia, Tennessee. The new pictures showing small changes to their appearance. Thomas' hair darkened red and Cummins' gray facial hair now brown. They bought food paying with cash and this morning authorities are still trying to determine if they were still traveling in Cummins' silver SUV. He was certainly putting a lot of planning into disappearing. He served what size mattress will fit in the back of a Nissan rogue. Can that particular model be traced via gps? Reporter: The two disappearing after Cummins was accused of having an inappropriate relationship with his teenage student allegedly writing intimate e-mails and even reportedly caught kissing Thomas. He was trying to romantically persuade her to come to him. Reporter: While authorities say they don't know where Cummins was planning to go, they are now saying they do know that he packed warm weather clothes, shorts and t-shirts for this trip. Please, if you have a sighting call 911 as soon as possible. That's the only way we can move forward. Reporter: This morning investigators say they have no idea where the two could be but these new images giving her family new hope. I feel at least hopeful that I've seen her, Elizabeth, if you can hear me, please come back to us. Reporter: Now Cummins' wife who had publicly pleaded for him to release Elizabeth has now filed for divorce and the reward to find these two is now at $10,000. Just a reminder how important these tips are this morning, George. Thanks very much. More now from our special consultant and former FBI agent Brad Garrett. Brad, thanks for joining us. Let's start out with surveillance video that shows some interaction between them. What does it tell you? Well, the one in the Walmart store, watch. He's in front of her. It looks like it at times she's not looking very happy. He's not physically controlling her but it looks like to me he's continualing to psychologically control her. Well, yeah, you would think that has to be the case given how long they've been together at this point. And now the net is so wide. Well, the net is wide, George, but if, in fact, this new sighting and I question whether that's accurate or not in kearney, Nebraska, as to what direction they're going. One thing fugitives do, George, is they go directions where they have been. For example, does he have any history in the west? Did he work thery does he have an ex-wife? Does he have children? All of those things because we tend to go to places we have a history. What is it about the photo ma takes you question it. Well, there's something different about the facial hair in the photograph in kearney, Nebraska, so I would like to see a better photograph before I made a decision as to whether that's the two of them. Okay, Brad Garrett, thanks very much.

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