I was just watching Investigation Discovery. They had a Walmart receipt. By scanning the bar code on it they pulled up the camera video showing the entrance just before the purchase and one over the top of the register at the time of the purchase. So, a Walmart receipt can definitely show evidence of purchases used in crimes. A Lowes receipt showed the time and video when more things were purchased to commit the crime.... Little things mean a lot...
Dudley, are these investigations on that show. I'm not familiar with it, but it looks very interesting!