In the dark of the night!

Every night before I go to bed, I check on the girls. I tuck all their blankets back on, kiss their little heads and head off to my bedroom to go to bed. Last night, after I finished my bedtime routine, I heard the toilet running in the girls bathroom. I walked back down the hall....no one was there. I looked back into their rooms...no one had moved...AT ALL...not even an inch. They were EXACTLY as I had left them! So naturally...I completely freak out! Who flushed the toilet??? I know it wasn't Kev because 1. He isn't a quiet person and 2. He was also dead asleep. So I ran back to my bedroom and woke him up..."Kev, go check the house. Someone flushed the toilet and it wasn't the girls!!!" (Please tell me I'm not the only wife to make her husband go check out freaky noises in the middle of the night !). Now, Kev IS THE WORST person to wake up. He is completely incoherent and has no idea what is going on! He starts complaining that I'm waking him up! Somehow he manages to get up, stumbles down to the bathroom, and looks INSIDE the toilet and exclaims, "There's no one here"! No kidding! So I make HIM look behind the shower curtain (because there's no way I'm looking there) and then I proceed to make him look in every closet, room, crevasse of the house! I even made him look in the garage and in the cars (just in case)! Unfortunately, once he "came to" he just laughed at me the entire time he was checking for the mysterious toilet flusher! So in the end, I still have no idea who flushed the toilet. It's just another night of many where I make him check out the freaky noises!