Jehoram King of Judah

4 When Jehoram established himself firmly over his father’s kingdom, he put all his brothers to the sword along with some of the officials of Israel.

Read 2 Chronicles 21:4 Using Other Translations

Now when Jehoram was risen up to the kingdom of his father, he strengthened himself, and slew all his brethren with the sword, and divers also of the princes of Israel.
When Jehoram had ascended the throne of his father and was established, he killed all his brothers with the sword, and also some of the princes of Israel.
But when Jehoram had become solidly established as king, he killed all his brothers and some of the other leaders of Judah.