The cause of its disappearance was a muffled sound that had occurred outside the window.

The cause of its disappearance is almost certainly climate change.

Whatever the cause of Kahlan's disappearance, it had all started that morning just before the fight when he'd been shot with the arrow.

The exact cause of her disappearance remains a mystery.

From his point of view, that encounter was the cause of her disappearance.

The wreckage has never been located nor the actual cause of her disappearance determined.

Is this the true cause of their disappearance?

And knowing the cause of Kowalski's disappearance, he felt unhappy about it.

Habitat destruction was probably the main cause of its disappearance.

The cause of the plane's disappearance remained a mystery yesterday.