Exodus 12:29-30

29So it came about at midnight that Adonai struck down all the firstborn in the land of Egypt, from the firstborn of Pharaoh sitting on his throne to the firstborn of the captive who was in the dungeon, and all the firstborn cattle.

30Then Pharaoh rose up in the night, he and all his servants and all the Egyptians, and there was loud wailing in Egypt. For there was not a house where someone was not dead.