. >> well, that receipt started making me believe that mrs. garviner made it to key west. >> a check of mike's credit card activity revealed he stopped at a convenience store in miami on the way down to key west. but the store's security camera showed mike was there alone. >> and we just thought it was odd that after driving that long that shirley wouldn't be coming in there to go to the bathroom, get something to drink. you know, we never see shirley coming into the store. >> next, police checked the security videotapes located in the toll booths between jacksonville and key west. they screened hundreds of hours of videotape until they found mike garvin's white jaguar. >> you see the car going through. you see it stopping to pay the toll and then driving on through. >> when they enlarged the picture, they saw an empty passenger seat. >> we ask him where shirley was sitting in the car. he said she was sitting in the front seat. we asked him if she ever got in the back seat. no, she never got in the back seat. she never reclined the seat. so, at this