that was his alibi. so stephanie went looking for copies of receipts to back up the alibi. so this is the store where supposedly gary down to came to do some shopping? >> one of the places we had to check out his alibi. the store had boxes and boxes of records, the old-fashioned sign slip kind of mercy. >> he's not kidding. boxes going back years. steffy rooted through piles of forgotten paper. >> how many boxes did you go? through >> i have no idea. >> i don't remember. >> hours an hours? >> i think i've tried to forget that. >> and just when steffy felt it was all a wasted effort, he pulled out this scrap. did you find it? >> i found it. i found it. >> there it was. a receipt that showed gary and his mom route shopping, all right. on december 13th. not the 15th, when they said