Matthew Poole and continuators on 2 Kings 11:3

3 And he was with her hid in the house of the LORD, six years : and Athaliah did reign over the land .

Either, Athaliah thought they were all Dead; or if she suspected that this was preserved, she thought an Infant could do her no great harm; and that she could so well assure the Kingdom to her self within a few years, that she need not fear any such weak Competitor; or she was willing to smother up the business, lest if she had made a strict and diligent search for it, the people should thereby learn, that there was yet a Son of David's Family left; and so be unquiet under her Government, and desirous of a Change.

Which she had an opportunity to do, because she was not onely the late Kings Wife, but also was probably made Queen-Regent upon Ioram's going to Ramoth-Gilead.