2 Chronicles 22:8-9

8So while Jehu was executing judgment on the house of Ahab, he found the rulers of Judah and the sons of Ahaziah’s brothers who were serving Ahaziah, and he killed them.

9Then Jehu looked for Ahaziah, and Jehu’s soldiers captured him while he was hiding in Samaria. So Ahaziah was brought to Jehu and put to death. They buried him, for they said, “He is the grandson of Jehoshaphat, who sought the LORD with all his heart.”

So no one was left from the house of Ahaziah with the strength to rule the kingdom.