2012 CLS battery missing from the trunk

Is this normal or did someone steal my battery?
Am I going crazy? It was locked in the garage all night and was never broken into. I did have it at the dealer for warranty work 4 months ago that dealt with the clock and radio. But it drove fine that entire time.
Is there a case where a 2012 CLS didn't have a battery in the trunk?
Thanks for any help.
Thanks for that info,
Everyone, from Battery stores to the dealership to online battery replacement sites, kept talking about the battery in the trunk needing to be replaced. I guess they all assumed I have the Eco function. I do not. Seems that I have the first few roll-out of 2012 model that didn't come with the Eco function.



