2 Chronicles 22:11 (KJV)

And he sought Ahaziah: and they caught him, (for he was hid in Samaria,) and brought him to Jehu: and when they had slain him, they buried him: Because, said they, he is the son of Jehoshaphat, who sought the Lord with all his heart. So the house of Ahaziah had no power to keep still the kingdom.

But when Athaliah the mother of Ahaziah saw that her son was dead, she arose and destroyed all the seed royal of the house of Judah.

But Jehoshabeath, the daughter of the king, took Joash the son of Ahaziah, and stole him from among the king’s sons that were slain, and put him and his nurse in a bedchamber. So Jehoshabeath, the daughter of king Jehoram, the wife of Jehoiada the priest, (for she was the sister of Ahaziah,) hid him from Athaliah, so that she slew him not.

And he was with them hid in the house of God six years: and Athaliah reigned over the land.