Your not wrong rosemommi79, he in fact probably holds the key to what happened.
When you take into account when Carl left Duffy's, and then went to Chevron to get a chicken-on-a-stick, I believe it was most likely Carl who picked up Andy to take him home.
One of the Duffy's staff members said that Cindy had left at around 12.15am. So it would have been Cindy who came home by herself.
Is it possible that the loud noise which he had initially thought was the dog rummaging through the garbage can, or could it have been a gun shot. Cindy had shot Andy and Carl was waiting near by, to help her to dispose of his body. And another p