2 Chronicles (Author Compiled by Isaiah and Ezra from records of Nathan, Gad, Iddo, Ahijah, Jehu and others.)
21:4And Jehoram established himself over the kingdom of his father, and strengthened himself; and he slew all his brethren with the sword, and certain also of the princes of Israel.
Original from The Bible Foundation - bf.org. They claim public domain status for their original text.