The Marbles Dropping Mystery

Many of us (silent sufferers) experience hearing sounds of dropping marbles permeating through ceilings in wee hours of the morning, which is quite quaint since (1) no child(ren) would be up so late playing with them (2) marbles aren't exactly commonplace nowadays (3) there's no one staying upstairs!

So what in the netherworld sired these unearthly noises? Could it be a jinn?

The SPI subsequently conducted a thorough investigation into and experimentation on this perturbing phenomenon. Their conclusion and expert analysis: False alarm, blame the pipework.

Are you convinced?