JudgeJoe, I'm not sure where you are getting the distance between Zebulon and Griffin.
Google is showing me 11.5 miles / 14 minute drive.
Just some miscellaneous thoughts ..
Apparently the Sewell residence was in a mobile home park, so I would think properties would not be too far apart from each other. If dogs had killed her outdoors, neighbors would have heard screaming, so it would seem she was deceased when she was put in the dog pen. I wish we had a visual of the yard to see where the dog pen was in relation to the house and in relation to other homes.
It was a Sunday which lends some credence to the claim that Mr. Sewell was visiting his mother out of town. He had a stepson, so did he live with his stepson and stepson's mother? If so, did they all go to Griffin with Mr. Sewell that day? If not, were they at the residence at any time that day?
If Mr. Sewell was in Griffin all day, he had no way of knowing how long the bike had been there (i.e. 5 minutes or 6 hours). IOW, if he did not know when Renee arrived, why the rush to bring the bike back to her parents? Before bringing the bike back, did he (his stepson, a wife ??) look around the property to see if Renee was in the yard? Did he check with any neighbours to enquire if Renee was with them? When he later found Renee's body, why not call the police instead of going back to tell the parents?