JONATHAN VIGLIOTTI:
00:01:01
How much harder does that likelihood get the further away we get from February 1, when she disappeared? It's probably exponentially harder by the day.
JONATHAN VIGLIOTTI:
00:01:09
Just blocks from Guthrie's home, retired Pima County lieutenant and former SWAT commander Bob Krygier showed us the challenges investigators are now facing in this desert terrain. We could stand here for days and probably never be seen, and we're 20 feet from the roadway, so this is the challenge that we have.
JONATHAN VIGLIOTTI:
00:01:27
As CBS News first reported, investigators continue to work with Walmart's management to identify the individual who purchased this backpack, sold exclusively at their stores. The sheriff says Walmart has handed over purchase records, including names. Could this backpack crack the case? Absolutely. That might be the only piece of evidence that shows up that can put two and two together. It could be very significant.
JONATHAN VIGLIOTTI:
00:01:52
CBS News has also learned the FBI is looking at gun purchases in the Tucson area. The owner of one gun store says an agent showed him several images with faces and names on them and also inquired about purchases made in the last year. And it is unclear if those photos and names are linked in any way to the search for the backpack. Meanwhile, the FBI continues to call on the public for help. Anyone with information is asked to call those numbers there on the screen, Tony.
TONY DOKOUPIL:
00:02:21
All right, Jonathan, thank you very much.
