perhaps videocams in bathroom? I don't suggest anyone go "get things" out of bathrooms that look suspicious. this story sounds hinky to me.
Have you ever been in an aircraft lavatory? There are three things in there, the sink, the toilet, and the smoke detector. It would be VERY easy to find something that looked out of the ordinary and not wired or attached directly to the aircraft, as it would need to be for several people to assemble it in stages.