Judges 3:23-25

23Then Ehud went out into the porch and closed the doors of the roof chamber behind him and locked them.

24When he had gone, the servants came, and when they saw that the doors of the roof chamber were locked, they thought, "Surely he is relieving himself in the closet of the cool chamber."

25And they waited till they were embarrassed. But when he still did not open the doors of the roof chamber, they took the key and opened them, and there lay their lord dead on the floor.