Siren-like noise coming from bathroom?

So im out of town right now and my mother called me this morning and along win my brother they.complained of a strange siren noise at 11:46 at night going off coming from their bathroom. I read that this was a wind spirit but it was not windy outside. They also told me that it faded and sounded like a moan afterwards. Like siren-fade-moan. And they fell asleep normally later and moving happened. Wth happenned? And yes I have pets but my mother said they were still asleep when the noise took place. She and my brother both awoke frightened. But no one made a sound. Wtf happenned in there?!