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.
KJV
For all the sins of Baasha, and the sins of Elah his son, by which they sinned, and by which they made Israel to sin, in provoking the LORD God of Israel to anger with their vanities.
ASV
for all the sins of Baasha, and the sins of Elah his son, which they sinned, and wherewith they made Israel to sin, to provoke Jehovah, the God of Israel, to anger with their vanities.