Ok, I seriously hate to rain on the Juan parade, but I listened again and I'm not sure this is as explosive as it seemed. If he has a business record from Walmart, that would be awesome and will lock it down that she lied about returning the gas can -- I had not really understood why she would have lied about this and failed to see the importance. But now I understand that the extra gas can is a whole lot more solid proof of premeditation than 2 gas cans.
I also haven't done the math, but I'm thinking that it would have been impossible for her to have used the amount of gas she says she used -- filling up twice between Pasadena and Mesa, plus 13 extra gallons in the trunk. I hope Juan drives this home on rebuttal.
As far as the Tesoro purchases go, if these turn out to be gas purchases, that's pretty important because of the fact that she tried to conceal the existence and use of the extra gas can. I think it's possible the extra purchase was not gasoline -- all we have right now is an implication, and I'd like to see some solid evidence.