tammy and sidney had been stalking heather. >> i would say you could compare their phone activity to anybody else's who lived and worked in the area. those are where the nightclubs are. there are restaurants there. it would appear that i were stalking her as well if you just looked at where my phone went. >> reporter: the defense said that what the jury really needed to understand was a simple fact. no piece of evidence put tammy at the landing. if anything, her alibi placed her miles away. >> did tammy's children stay in the house with you where your mother polly lives? >> yes. >> reporter: tammy's sister ashley told the court she was baby-sitting tammy's kids on the night of december 17, 2013. she said tammy and sidney went out together in the hours leading up to heather's disappearance. but ashley remembered when her sister came home. >> she texted me that night saying that she was home. >> do you know about what time that was?