You where spot on, they had raised a new queen. It is a hive that dad gave me, it has a solid base with a screen bottom sitting on top of it, with a gap between the two. I decided to carefully inspect each frame this morning, when I got into the bottom box I noticed a lot of bees on the bottom of the screen, in between the two. I set the box off and pulled up the screen bottom, in with the workers was a beautiful young queen. Evidently when she returned from here matting flight she went underneath and stayed.
She is now safely in the hive.

