This happened because of all the sins Baasha and his son Elah had committed and had caused Israel to commit, provoking the LORD, the God of Israel, to anger with their worthless idols.
Jewish Publication Society of America Version (JPS1917) - 1 Kings 16:13 >for all the sins of Baasa, and the sins of Elah his son, which they sinned, and wherewith they made Israel to sin, to provoke the LORD, the God of Israel, with their vanities.