Exodus 12:29-30

29And that night at midnight, the Lord struck down all the firstborn sons in the land of Egypt, from the firstborn son of Pharaoh, who sat on his throne, to the firstborn son of the prisoner in the dungeon. Even the firstborn of their livestock were killed.

30Pharaoh and all his officials and all the people of Egypt woke up during the night, and loud wailing was heard throughout the land of Egypt. There was not a single house where someone had not died.